What hormone is responsible for human growth?
Growth hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in human development. It is a type of mitogen which is specific only to certain kinds of cells. Growth hormone is a 191-amino acid, single-chain polypeptide that is synthesized, stored and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland.
Choh Hao Li
Choh Hao Li (sometimes "Cho Hao Li") (; April 21, 1913 – November 28, 1987) was a Chinese-born U.S. biochemist who discovered, in 1966, that human pituitary growth hormone (somatotropin) consists of a chain of 256 amino acids. In 1970 he succeeded in synthesizing this hormone, the largest protein molecule synthesized up to that time.
Androgen
An androgen (from Greek "andr-", the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes the embryological development of the primary male sex organs, and the development of male secondary sex characteristics at puberty. Androgens are synthesized in the testes, the ovaries, and the adrenal glands.
Somatotropic cell
If there is an excess of growth hormone, it is usually because of over-secretion of somatotrope cells in the anterior pituitary gland. A significant amount of excess somatotrope secretion before puberty or before the end of new bone tissue growth can lead to gigantism, a disease that causes excess growth of body (e.g. being over 7 ft. tall) and unusually long limbs. An excess of secretion of growth hormone after puberty can lead to acromegaly. This is a disease that causes abnormal growth in the hands, head, jaw, and tongue. Some symptoms associated with acromegaly include heavy sweating, oily skin, improper processing of sugars in the diet (diabetes), high blood pressure, increased calcium in urine and swelling of the thyroid gland and arthritis.
Hair
Evolutionary biologists suggest that the genus "Homo" arose in East Africa approximately 2.5 million years ago. They devised new hunting techniques. The higher protein diet led to the evolution of larger body and brain sizes. Jablonski postulates that increasing body size, in conjunction with intensified hunting during the day at the equator, gave rise to a greater need to rapidly expel heat. As a result, humans evolved the ability to sweat: a process which was facilitated by the loss of body hair. A major problem with this theory, however, is that it does not explain why males are larger, hairier, and were more active in hunting than females. The female-male size differential among other closely associated primates is much greater than among humans, and therefore it was reduced during human evolution.
Other primates have sweat gland in their armpits that function as those of humans, and thus it is probable that human sweat glands evolved from a similar distribution, spreading to more areas of the body, rather than occurring through evolution of a new trait. It is not known whether the increased distribution of sweat glands occurred before, during, or after, the change in body hair, or even whether the two are related developments. Horses also sweat, and they are larger, hairier, and expend more energy running than human males, so there may not be any connection between the ability to sweat and the apparent hairlessness of humans.
Gonadotropin release inhibitor
The hormone of gonadotropins secreted by the anterior hypophyse gland effects on the gonads and play a crucial role in the process of gonadal development and function in vertebrates. In birds and mammals, luteinizinghormone (LH) regulates sex steroid production as well as ovulation, whereas follicle stimulating hormone (FSH) promotes spermatogenesis and ovarian follicle maturation. Since the isolation of gonadotropin-releasing hormone (GnRH), a hypothalamic decapeptide, from mammalian brain in the early 1970s, several other GnRHs have been identified in the brains of other vertebrates. Based on extensive studies in vertebrates, it was generally believed that GnRH is the only hypothalamic regulator of the release of pituitary gonadotropins. Some neurochemicals and peripheral hormones [e.g.gamma-aminobutyric acid (GABA), opiates, gonadal sex steroids, inhibin] can modulate gonadotropin release, but GnRH was considered to have no hypothalamic antagonist.
American Academy of Anti-Aging Medicine
"The New York Times" reports that the idea that growth hormone can improve "health, energy level and sense of well-being." is a core belief of the A4M, with Klatz writing a book in 1998 entitled "Grow Young with HGH: The Amazing Medically Proven Plan to Reverse Aging" where he states "The ‘Fountain of Youth’ lies within the cells of each of us. All you need to do is release it". A 2005 review in the "Journal of Endocrinological Investigation" noted the long history of these ideas, but stated that the "concept of a 'hormonal fountain of youth' is predominantly mythological." Nevertheless, Klatz maintains that growth hormone reverses aging as a physical process and has described growth hormone as "the first medically proven age-reversal therapy." However, MSNBC reports that Daniel Rudman, the author of the 1990 study that sparked the movement, "issued many caveats and cautions about using HGH and never recommended its use to delay aging. In fact, he was horrified his study was being used to support the industry especially since heavy use of growth hormone can have unwanted side effects".
Dubowitz syndrome
Dubowitz syndrome is accompanied by a deficiency in growth hormone. People with Dubowitz syndrome have stunted growth, and growth hormones are secreted by the anterior pituitary of the brain. The main function of the anterior pituitary is to increase height during development. Other functions include regulating the immune system, increasing calcium retention, increasing muscle mass and stimulating gluconeogenesis. A deficiency in growth hormone may be caused by genetic mutations, malformations of the hypothalamus or pituitary gland during development, or damage to the pituitary. In Dubowitz syndrome, the cause is likely the underlying mutations or disruption of brain structures during development. Growth hormone deficiency also correlates with low levels of IgG antibodies, a condition found in Dubowitz patients.
Human penis size
Androgens like testosterone are responsible for penis enlargement and elongation during puberty. Penis size is positively correlated with increasing testosterone levels during puberty. However, after puberty, administration of testosterone is not capable of affecting penis size, and androgen deficiency in adult men only results in a small decrease in size. Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are also involved in penis size, with deficiency (such as that observed in growth hormone deficiency or Laron syndrome) at critical developmental stages having the potential to result in micropenis.
Growth hormone in sports
Researchers are still debating whether the more noticeable muscles are larger in size as well. It should be clarified, though, that muscle mass is not the same as muscle strength. Some say that human growth hormone will build muscle mass through raised insulin-like growth factors levels leading to heightened protein synthesis without any side effects while other researchers argue that there have been no such findings on young healthy adults. The second argument is more supported by research discoveries that HGH affects muscle protein synthesis no differently than a placebo does.
Examorelin
Examorelin substantially and dose-dependently increases plasma levels of growth hormone (GH) in animals and humans. In addition, similarly to pralmorelin (GHRP-2) and GHRP-6, it slightly and dose-dependently stimulates the release of prolactin, adrenocorticotropic hormone (ACTH), and cortisol in humans. There are conflicting reports on the ability of examorelin to elevate insulin-like growth factor 1 (IGF-1) and insulin-like growth factor-binding protein 1 (IGFBP-1) levels in humans, with some studies finding no increase and others finding a slight yet statistically significant increase. Examorelin does not affect plasma levels of glucose, luteinizing hormone (LH), follicle-stimulating hormone (FSH), or thyroid-stimulating hormone (TSH) in humans.
Growth hormone therapy
Cadaver growth hormone is the term for GH extracted from the pituitary glands of human cadavers between 1960 and 1985 for therapy of deficient children. In the U.S., cadaver GH, also referred to as NPA growth hormone, was provided by the National Pituitary Agency, and by other national programs and commercial firms as well. In 1985 it was associated with the development of Creutzfeldt–Jakob disease, and was withdrawn from use.
Adrenal gland
During early childhood androgen synthesis and secretion remain low, but several years before puberty (from 6–8 years of age) changes occur in both anatomical and functional aspects of cortical androgen production that lead to increased secretion of the steroids DHEA and DHEA-S. These changes are part of a process called adrenarche, which has only been described in humans and some other primates. Adrenarche is independent of ACTH or gonadotropins and correlates with a progressive thickening of the zona reticularis layer of the cortex. Functionally, adrenarche provides a source of androgens for the development of axillary and pubic hair before the beginning of puberty.
Gigantism
Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are two substances that have been identified as influencing growth plate formation and bone growth and, therefore, gigantism. Their specific mechanisms are still not well understood.
Thyroid hormones
The thyroid hormones act on nearly every cell in the body. They act to increase the basal metabolic rate, affect protein synthesis, help regulate long bone growth (synergy with growth hormone) and neural maturation, and increase the body's sensitivity to catecholamines (such as adrenaline) by permissiveness. The thyroid hormones are essential to proper development and differentiation of all cells of the human body. These hormones also regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds. They also stimulate vitamin metabolism. Numerous physiological and pathological stimuli influence thyroid hormone synthesis.
Acromegaly
Acromegaly is a disorder that results from excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There may also be enlargement of the forehead, jaw, and nose. Other symptoms may include joint pain, thicker skin, deepening of the voice, headaches, and problems with vision. Complications of the disease may include type 2 diabetes, sleep apnea, and high blood pressure.
Acromegaly is typically due to the pituitary gland producing too much growth hormone. In more than 95% of cases the excess production is due to a benign tumor, known as a pituitary adenoma. The condition is not inherited from a person's parents. Rarely acromegaly is due to tumors in other parts of the body. Diagnosis is by measuring growth hormone after a person has drunk glucose or by measuring insulin-like growth factor I in the blood. After diagnosis, medical imaging of the pituitary is carried out to look for an adenoma. If excess growth hormone is produced during childhood the result is gigantism.
Treatment options include surgery to remove the tumor, medications, and radiation therapy. Surgery is usually the preferred treatment and is most effective when the tumor is smaller. In those in whom surgery is not effective, medications of the somatostatin analogue or GH receptor antagonist type may be used. The effects of radiation therapy are more gradual than that of surgery or medication. Without treatment those affected live on average 10 years less; with treatment, however, life expectancy is typically normal.
Acromegaly affects about 6 per 100,000 people. It is most commonly diagnosed in middle age. Males and females are affected with equal frequency. The first medical description of the disorder occurred in 1772 by Nicolas Saucerotte. The term is from Greek "akron" meaning "extremity" and "mega" meaning "large".
Features that result from high level of GH or expanding tumor include:About 98% of cases of acromegaly are due to the overproduction of growth hormone by a benign tumor of the pituitary gland called an adenoma. These tumors produce excessive growth hormone and compress surrounding brain tissues as they grow larger. In some cases, they may compress the optic nerves. Expansion of the tumor may cause headaches and visual disturbances. In addition, compression of the surrounding normal pituitary tissue can alter production of other hormones, leading to changes in menstruation and breast discharge in women and impotence in men because of reduced testosterone production.
James Mourilyan Tanner
Tanner did early research on the use of human growth hormone to address children whose growth was significantly delayed and was responsible for selecting the small handful of children in the UK who would be treated with the limited supply of HGH extracted from human cadavers. After a number of patients worldwide died in 1985 due to an infectious brain disease spread by the HGH treatments, Tanner immediately stopped the therapy, but had patients who insisted that they were willing to take the risk to address their child's delayed growth. Treatments resumed in the 1990s following the introduction of genetically engineered human growth hormone.
Triiodothyronine
Triiodothyronine, also known as T, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate.
Mecasermin
Mecasermin () (brand name Increlex), also known as recombinant human insulin-like growth factor-1 (rhIGF-1), is recombinant form of human insulin-like growth factor 1 (IGF-I) which is used for the long-term treatment of growth failure and short stature in children with severe primary IGF-I deficiency, for instance due to growth hormone deficiency or Laron syndrome (growth hormone insensitivity).
Estrogen
While estrogens are present in both men and women, they are usually present at significantly higher levels in women of reproductive age. They promote the development of female secondary sexual characteristics, such as breasts, and are also involved in the thickening of the endometrium and other aspects of regulating the menstrual cycle. In males, estrogen regulates certain functions of the reproductive system important to the maturation of sperm and may be necessary for a healthy libido.Estrogens are responsible for the development of female secondary sexual characteristics during puberty, including breast development, widening of the hips, and female fat distribution. Conversely, androgens are responsible for pubic and body hair growth, as well as acne and axillary odor.
Growth hormone 1
Growth hormone 1, also known as pituitary growth hormone or simply as growth hormone (GH) or somatotropin, is a protein that in humans is encoded by the "GH1" gene.
Sexual orientation
For humans, the norm is that females possess two X sex chromosomes, while males have one X and one Y. The default developmental pathway for a human fetus being female, the Y chromosome is what induces the changes necessary to shift to the male developmental pathway. This differentiation process is driven by androgen hormones, mainly testosterone and dihydrotestosterone (DHT). The newly formed testicles in the fetus are responsible for the secretion of androgens, that will cooperate in driving the sexual differentiation of the developing fetus, including its brain. This results in sexual differences between males and females. This fact has led some scientists to test in various ways the result of modifying androgen exposure levels in mammals during fetus and early life.
Cholodny–Went model
The model was independently proposed by the Russian scientist Nikolai Cholodny of the University of Kiev in 1927 and by Frits Warmolt Went of the California Institute of Technology in 1928, both based on work they had done in 1926.
The basic elements of the theory are that auxin is the sole hormone that controls growth in gravitropism and phototropism; the rate of growth depends on the concentration of auxin; and both gravity and unidirectional light affect the movement of auxin.
The original theory predicts that since the growth factor would move from the lighted side to the shady side, growth would slow on the lighted side and speed up on the shady side, so the stem will begin to bend toward the light source.
Growth hormone therapy
Growth hormone therapy refers to the use of growth hormone (GH) as a prescription medication—it is one form of hormone therapy. Growth hormone is a peptide hormone secreted by the pituitary gland that stimulates growth and cell reproduction. In the past, growth hormone was extracted from human pituitary glands. Growth hormone is now produced by recombinant DNA technology and is prescribed for a variety of reasons. GH therapy has been a focus of social and ethical controversies for 50 years.
Testosterone
Testosterone is necessary for normal sperm development. It activates genes in Sertoli cells, which promote differentiation of spermatogonia. It regulates acute HPA (hypothalamic–pituitary–adrenal axis) response under dominance challenge. Androgen including testosterone enhances muscle growth. Testosterone also regulates the population of thromboxane A receptors on megakaryocytes and platelets and hence platelet aggregation in humans.
Gi alpha subunit
It is also attributed a minor role in activation of the phospholipase C pathway. Growth hormone is required for normal postnatal growth, bone growth, regulatory effects on protein, carbohydrate, and lipid metabolism. Although this is mainly a function of the G alpha subunit.
Herbert McLean Evans
His medical research at Berkeley addressed problems relating to human nutrition, endocrinology, embryology, and histology. In 1918, his research into the number of human chromosomes led him to believe the number to be 48, when most people assumed the number to be much higher. It was only later discovered that the correct figure was 46. Evans had much greater success however with hormones extracted from the anterior lobe of the pituitary gland. He isolated Human Growth Hormone, which is essential for human growth and development. In 1922 along with Katharine Scott Bishop, during feeding experiments on rats, he co-discovered Vitamin E which is needed for human reproduction. Evans became director of the Institute of Experimental Biology at Berkeley in 1931. With Gladys Anderson Emerson, he reported the isolation of the pure Vitamin E from wheat germ in 1937. He also determined the formula CHO. Evans was also instrumental in developing reproductive systems research with Miriam Elizabeth Simpson and Choh Hao Li, by studying the oestrus cycle of rats. Evans is also credited with developing Evans blue, a method which determines blood volume in humans and animals.
Retinol
Vitamin A affects the production of human growth hormone. Retinoic acid is required to bind to nuclear receptors to aid in growth.
Growth hormone
Secretion of growth hormone (GH) in the pituitary is regulated by the neurosecretory nuclei of the hypothalamus. 
These cells release the peptides Growth hormone-releasing hormone (GHRH or "somatocrinin") and Growth hormone-inhibiting hormone (GHIH or "somatostatin") into the hypophyseal portal venous blood surrounding the pituitary.
GH release in the pituitary is primarily determined by the balance of these two peptides, which in turn is affected by many physiological stimulators (e.g., exercise, nutrition, sleep) and inhibitors (e.g., free fatty acids) of GH secretion.
Growth hormone therapy
RHGH (rHGH, rhGH) refers to recombinant human growth hormone, that is, somatropin (INN). Its amino acid sequence is identical with that of endogenous human GH.
Tris(1,3-dichloro-2-propyl)phosphate
TDCPP may affect brain development and function via the thyroid system. Thyroid hormones are critical for normal growth and development and for proper function in the endocrine system. The developing brain in particular is highly sensitive to thyroid hormone disruptions. Disruptions to the thyroid system of either the mother or the fetus during early brain development are associated with lower IQ scores and increased risk for ADHD or other neurobehavioral disorders.
Human reproductive ecology
Puberty is the transitory stage in human development in which a person goes from a child into a reproductively mature adult, in other words, puberty is the process of sexual maturation in humans. The onset of puberty varies between boys and girls, with boys usually starting around 11–12 years of age and ending by 16-17, and girls starting around 10-11 and ending at 15-17. Activity in the hypothalamic–pituitary–gonadal axis (HPG axis) initiates puberty by secreting gonadotropin-releasing hormone (GnRH) from the hypothalamus into the anterior pituitary. The anterior pituitary releases the gonadotropins luteunizing hormone (LH) into the ovaries, which produce estrogen, and follicle-stimulating hormone (FSH) into the testes, which produce testosterone. The central event in puberty for females is menarche, the first menstrual bleeding. For males, it is the first ejaculation. The onset of menarche is easier to determine due to the evidence of menstrual bleeding, while the first ejaculation for males is usually self reported. In evolutionary context, it is assumed that human physiology has been modeled through natural selection to maximize reproductive success by allotting energy and resources through trade-offs.
Anamorelin
Anamorelin significantly increases plasma levels of growth hormone (GH), insulin-like growth factor 1 (IGF-1), and insulin-like growth factor-binding protein 3 (IGFBP-3) in humans, without affecting plasma levels of prolactin, cortisol, insulin, glucose, adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), or thyroid-stimulating hormone (TSH). In addition, anamorelin significantly increases appetite, overall body weight, lean body mass, and muscle strength, with increases in body weight correlating directly with increases in plasma IGF-1 levels.
National Organization of Short Statured Adults
NOSSA announced its opposition to the use of human growth hormone for short, but otherwise healthy, children. The organization believes being short isn’t a problem; the real difficulties lies in the social bias against short people. In part to define the organization's position on the matter, NOSSA representative and author Ellen Frankel LCSW stated, "What we need is education for those who discriminate against short people, not the genetic engineering of the victims of that prejudice." Frankel states, "The growth hormone deficient child suffers from an underlying medical problem that affects the body's health in different ways. The non-growth-hormone-deficient child has no underlying medical problem. They simply present as a variation on the norm with regard to height. The decision to medically intervene on the healthy child's stature is socially based due to height discrimination and prejudice."
Mammary gland
Estrogen and growth hormone (GH) are essential for the ductal component of mammary gland development, and act synergistically to mediate it. Neither estrogen nor GH are capable of inducing ductal development without the other. The role of GH in ductal development has been found to be mostly mediated by its induction of the secretion of insulin-like growth factor 1 (IGF-1), which occurs both systemically (mainly originating from the liver) and locally in the mammary fat pad through activation of the growth hormone receptor (GHR). However, GH itself also acts independently of IGF-1 to stimulate ductal development by upregulating estrogen receptor (ER) expression in mammary gland tissue, which is a downstream effect of mammary gland GHR activation. In any case, unlike IGF-1, GH itself is not essential for mammary gland development, and IGF-1 in conjunction with estrogen can induce normal mammary gland development without the presence of GH. In addition to IGF-1, other paracrine growth factors such as epidermal growth factor (EGF), transforming growth factor beta (TGF-β), amphiregulin, fibroblast growth factor (FGF), and hepatocyte growth factor (HGF) are involved in breast development as mediators downstream to sex hormones and GH/IGF-1.
Muscle hypertrophy
Individual differences in genetics account for a substantial portion of the variance in existing muscle mass. A classical twin study design (similar to those of behavioral genetics) estimates that about 52% of the variance in lean body mass is estimated to be heritable and that about 45% of the variance in muscle fiber proportion is genetic as well. 
During puberty in males, hypertrophy occurs at an increased rate. Natural hypertrophy normally stops at full growth in the late teens. As testosterone is one of the body's major growth hormones, on average, males find hypertrophy much easier (on an absolute scale) to achieve than females and on average, have about 60% more muscle mass than women. Taking additional testosterone, as in anabolic steroids, will increase results. It is also considered a performance-enhancing drug, the use of which can cause competitors to be suspended or banned from competitions. Testosterone is also a medically regulated substance in most countries, making it illegal to possess without a medical prescription. Anabolic steroid use can cause testicular atrophy, cardiac arrest, and gynecomastia.
Growth hormone deficiency
As an adult ages, it is normal for the pituitary to produce diminishing amounts of GH and many other hormones, particularly the sex steroids. Physicians therefore distinguish between the natural reduction in GH levels which comes with age, and the much lower levels of "true" deficiency. Such deficiency almost always has an identifiable cause, with adult-onset GHD "without" a definable cause ("idiopathic GH deficiency") extremely rare. GH does function in adulthood to maintain muscle and bone mass and strength, and has poorly understood effects on cognition and mood.
Congenital adrenal hyperplasia
Cortisol is an adrenal steroid hormone that is required for normal endocrine function. Production begins in the second month of fetal life. Poor cortisol production is a hallmark of most forms of CAH. Inefficient cortisol production results in rising levels of ACTH, because cortisol feeds back to inhibit ACTH production, so loss of cortisol results in increased ACTH. This increased ACTH stimulation induces overgrowth ("hyperplasia") and overactivity of the steroid-producing cells of the adrenal cortex. The defects causing adrenal hyperplasia are "congenital" (i.e. present at birth).
Prostaglandin D2
A 2012 research paper indicates a causal link between elevated levels of localized PGD and hair growth inhibition. Applied topically, the researchers found PGD prevents hair growth, and mice that were genetically inclined to produce higher levels of PGD had inhibited hair growth. The researchers also found PGD levels were much higher in balding scalp tissue than nonbalding scalp tissue, through increased levels of prostaglandin D2 synthase. The paper suggested that inhibition of hair growth involved binding of PGD to a receptor called GPR44, and that GPR44 therefore would be a therapeutic target for androgenic alopecia in both men and women with hair loss and thinning. Because PGD's relation to asthma has been known for several years, several drugs that seek to reduce the effect of PGD through blocking the GPR44 are already in clinical trials.
Pattern hair loss
Transgenic studies have shown that growth and dormancy of hair follicles are related to the activity of insulin-like growth factor (IGF) at the dermal papillae, which is affected by DHT. Androgens are important in male sexual development around birth and at puberty. They regulate sebaceous glands, apocrine hair growth, and libido. With increasing age, androgens stimulate hair growth on the face, but can suppress it at the temples and scalp vertex, a condition that has been referred to as the 'androgen paradox'.
Growth hormone
A recombinant form of hGH called somatropin (INN) is used as a prescription drug to treat children's growth disorders and adult growth hormone deficiency. In the United States, it is only available legally from pharmacies, by prescription from a doctor. In recent years in the United States, some doctors have started to prescribe growth hormone in GH-deficient older patients (but not on healthy people) to increase vitality. While legal, the efficacy and safety of this use for HGH has not been tested in a clinical trial. At this time, HGH is still considered a very complex hormone, and many of its functions are still unknown.
Testosterone
Testosterone is the primary male sex hormone and an anabolic steroid. In male humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair. In addition, testosterone is involved in health and well-being, and the prevention of osteoporosis. Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss.
Development of the human body
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Until the maturation of their reproductive capabilities, the pre-pubertal physical differences between boys and girls are the external sex organs.
Plant hormone
Gibberellins (GAs) include a large range of chemicals that are produced naturally within plants and by fungi. They were first discovered when Japanese researchers, including Eiichi Kurosawa, noticed a chemical produced by a fungus called "Gibberella fujikuroi" that produced abnormal growth in rice plants. It was later discovered that GAs are also produced by the plants themselves and they control multiple aspects of development across the life cycle. The synthesis of GA is strongly upregulated in seeds at germination and its presence is required for germination to occur. In seedlings and adults, GAs strongly promote cell elongation. GAs also promote the transition between vegetative and reproductive growth and are also required for pollen function during fertilization.
Puberty
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy. In response to the signals, the gonads produce hormones that stimulate libido and the growth, function, and transformation of the brain, bones, muscle, blood, skin, hair, breasts, and sex organs. Physical growth—height and weight—accelerates in the first half of puberty and is completed when an adult body has been developed. Until the maturation of their reproductive capabilities, the pre-pubertal physical differences between boys and girls are the external sex organs.
Growth hormone
Increased height during childhood is the most widely known effect of GH. Height appears to be stimulated by at least two mechanisms:In addition to increasing height in children and adolescents, growth hormone has many other effects on the body:
Estradiol
Estradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Estradiol is responsible for the development of female secondary sexual characteristics such as the breasts, widening of the hips, and a feminine pattern of fat distribution in women and is important in the development and maintenance of female reproductive tissues such as the mammary glands, uterus, and vagina during puberty, adulthood, and pregnancy. It also has important effects in many other tissues including bone, fat, skin, liver, and the brain. Though estradiol levels in men are much lower compared to those in women, estradiol has important roles in men as well. Aside from humans and other mammals, estradiol is also found in most vertebrates and crustaceans, insects, fish, and other animal species.
Hypothalamic–pituitary–gonadal axis
The axis controls development, reproduction, and aging in animals. Gonadotropin-releasing hormone (GnRH) is secreted from the hypothalamus by GnRH-expressing neurons. The anterior portion of the pituitary gland produces luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and the gonads produce estrogen and testosterone.
Breast development
Progesterone, in conjunction with GH/IGF-1 similarly to estrogen, affects the development of the breasts during puberty and thereafter as well. To a lesser extent than estrogen, progesterone contributes to ductal development at this time, as evidenced by the findings that progesterone receptor (PR) knockout mice or mice treated with the PR antagonist mifepristone show delayed (albeit eventually normal, due to estrogen acting on its own) ductal growth during puberty and by the fact that progesterone has been found to induce ductal growth on its own in the mouse mammary gland mainly via the induction of the expression of amphiregulin, the same growth factor that estrogen primarily induces to mediate its actions on ductal development. In addition, progesterone produces modest lobuloalveolar development (alveolar bud formation or ductal sidebranching) starting at puberty, specifically through activation of PRB (and notably not PRA), with growth and regression of the alveoli occurring to some degree with each menstrual cycle. However, only rudimentary alveoli develop in response to pre-pregnancy levels of progesterone and estrogen, and lobuloalveolar development will remain at this stage until pregnancy occurs, if it does. In addition to GH/IGF-1, estrogen is required for progesterone to affect the breasts, as estrogen primes the breasts by inducing the expression of the progesterone receptor (PR) in breast epithelial tissue. In contrast to the case of the PR, ER expression in the breast is stable and differs relatively little in the contexts of reproductive status, stage of the menstrual cycle, or exogenous hormonal therapy.
Human placental lactogen
hPL has weak actions similar to those of growth hormone, causing the formation of protein tissues in the same way that growth hormone, but 100 times more hPL than growth hormone is required to promote growth. However, hPL has a blood level of more than 50 times that of hGH, hence its effects must not be ignored. An enhancer for the human placental lactogen gene is found 2 kb downstream of the gene and participates in the cell-specific control gene expression.
Dwarfism in chickens
Among the main factors involved in growth regulation, thyroid hormones tiroxine (T4) triiodothyronine (T3), growth hormone (GH), and its related growth factor, Insulin-like growth factor-I (IGF-I), were the most studied in dwarfs.
Growth hormone–releasing hormone
Growth hormone–releasing hormone (GHRH), also known as somatocrinin or by several other names in its endogenous forms and as somatorelin (INN) in its pharmaceutical form, is a releasing hormone of growth hormone (GH). It is a 44-amino acid peptide hormone produced in the arcuate nucleus of the hypothalamus.
Daphne Osborne
The hormonal control of growth, differentiation and development in plants was Osborne's lifelong interest. She is particularly known for her work establishing that the gas ethylene is a natural plant hormone, rather than a by-product or pollutant, and for demonstrating that ethylene, rather than abscisic acid, is the major regulator of senescence (ageing) and abscission (shedding of parts such as leaves). She conducted extensive research into interactions between ethylene and auxin (another key plant hormone) in controlling numerous aspects of plant development. This work led her to develop the idea of the target cell as a model for how a small number of plant hormones can exert many different effects, a concept she expounded in her 2005 book, "Hormones, Signals and Target Cells in Plant Development" (co-authored with Michael McManus).
Another major focus of Osborne's research was seed biology. An expert on seed ageing and plant DNA repair, Osborne researched the effects of DNA degradation, repair and telomere length on the viability of seeds. In the 1970s, she was among the earliest to attempt to isolate nucleic acids from ancient seeds, finding that only very short fragments could be isolated from grains from Egyptian tombs. Among her final research projects was a study of the effects on DNA repair in seeds and pollen of exposure to radioactive fallout after the Chernobyl nuclear reactor explosion.
Growth hormone receptor
This gene encodes a protein that is a transmembrane receptor for growth hormone. Binding of growth hormone to the receptor leads to reorientation of a pre-assembled receptor dimer dimerization (the receptor may however also exist as monomers on the cell surface ) and the activation of an intra- and intercellular signal transduction pathway leading to growth. A common alternate allele of this gene, called GHRd3, lacks exon three and has been well characterized. Mutations in this gene have been associated with Laron syndrome, also known as the growth hormone insensitivity syndrome (GHIS), a disorder characterized by short stature (proportional dwarfism). Other splice variants, including one encoding a soluble form of the protein (GHRtr), have been observed but have not been thoroughly characterized. Laron mice (that is mice genetically engineered to carry defective Ghr), have a dramatic reduction in body mass (only reaching 50% of the weight of normal siblings), and also show a ~40% increase in lifespan.
Progesterone
Though to a far lesser extent than estrogen, which is the major mediator of mammary ductal development (via the ERα), progesterone has been found to be involved in ductal development of the mammary glands to some extent as well. PR knockout mice or mice treated with the PR antagonist mifepristone show delayed although otherwise normal mammary ductal development at puberty. In addition, mice modified to have overexpression of PRA display ductal hyperplasia, and progesterone induces ductal growth in the mouse mammary gland. Progesterone mediates ductal development mainly via induction of the expression of amphiregulin, the same growth factor that estrogen primarily induces the expression of to mediate ductal development. These animal findings suggest that, while not essential for full mammary ductal development, progesterone seems to play a potentiating or accelerating role in estrogen-mediated mammary ductal development.
Plant hormone
Plant hormones (also known as phytohormones) are signal molecules produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development. Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones. The term 'phytohormone' was coined by Went and Thimann and used in the title of their book in 1937.
Growth hormone in sports
Growth hormone in sports are one of the few legal steroids in 2018. It refers to the use of growth hormones (GH or HGH) for athletic enhancement, as opposed to growth hormone treatment for medical therapy. Human Growth Hormone is a prescription medication, meaning that its distribution and use without a prescription is illegal. There is limited evidence that GH doping improves athletic performance, although the perception that it does is common in the sporting community. Potential side effects of long term GH doping could mirror the symptoms found in sufferers of acromegaly, a disease in which the anterior pituitary gland produces excess growth hormone.
Calmodulin
1) DWF1 in "Arabidopsis" is a protein that plays an enzymatic role in the biosynthesis of a steroid hormone in plants that is required for plant growth called, brassinosteroid. An interaction occurs between CaM and DWF1 and DWF1 unable to bind CaM is unable to produce a regular growth phenotype in plants. Hence, CaM is essential for the DWF1 function in plant growth.
Primordial dwarfism
It is known that PD is caused by inheriting a mutant gene from each parent. The lack of normal growth in the disorder is not due to a deficiency of growth hormone, as in hypopituitary dwarfism. Administering growth hormone, therefore, has little or no effect on the growth of the individual with primordial dwarfism, except in the case of Russell–Silver syndrome (RSS). Individuals with RSS respond favorably to growth hormone treatment. Children with RSS that are treated with growth hormone before puberty may achieve several inches of additional height. In January 2008, it was published that mutations in the pericentrin gene (PCNT) were found to cause primordial dwarfism. Pericentrin has a role in cell division, proper chromosome segregation and cytokinesis.
Muscle
Biological factors such as age and hormone levels can affect muscle hypertrophy. During puberty in males, hypertrophy occurs at an accelerated rate as the levels of growth-stimulating hormones produced by the body increase. Natural hypertrophy normally stops at full growth in the late teens. As testosterone is one of the body's major growth hormones, on average, men find hypertrophy much easier to achieve than women. Taking additional testosterone or other anabolic steroids will increase muscular hypertrophy.
Ora Mendelsohn Rosen
Ora Mendelsohn Rosen (October 26, 1935 – May 30, 1990) was an American medical researcher who investigated the influence of hormones, particularly insulin, on the control of cell growth. She was a professor at the Albert Einstein College of Medicine and Memorial Sloan Kettering Cancer Center and a member of the National Academy of Sciences.
Growth hormone deficiency
GH deficiency is treated by replacing GH with daily injections under the skin or into muscle. Until 1985, growth hormone for treatment was obtained by extraction from human pituitary glands collected at autopsy. Since 1985, recombinant human growth hormone (rHGH) is a recombinant form of human GH produced by genetically engineered bacteria, manufactured by recombinant DNA technology. In both children and adults, costs of treatment in terms of money, effort, and the impact on day-to-day life, are substantial.
Growth hormone
Athletes in many sports have used human growth hormone in order to attempt to enhance their athletic performance. Some recent studies have not been able to support claims that human growth hormone can improve the athletic performance of professional male athletes. Many athletic societies ban the use of GH and will issue sanctions against athletes who are caught using it. However, because GH is a potent endogenous protein, it is very difficult to detect GH doping. In the United States, GH is legally available only by prescription from a medical doctor.
Hair care
Scalp hair grows, on average, at a rate of about 1.25 centimeters per month, and shampoos or vitamins have not been shown to noticeably change this rate. Hair growth rate also depends upon what phase in the cycle of hair growth one is actually in; there are three phases. The speed of hair growth varies based upon genetics, gender, age, hormones, and may be reduced by nutrient deficiency (i.e., anorexia, anemia, zinc deficiency) and hormonal fluctuations (i.e., menopause, polycystic ovaries, thyroid disease).
Ghrelin
Ghrelin was discovered after the ghrelin receptor (called growth hormone secretagogue type 1A receptor or GHS-R) was discovered in 1996 and was reported in 1999. The hormone name is based on its role as a "growth hormone-releasing peptide", with reference to the Proto-Indo-European root "gʰre-", meaning "to grow".
ALOX12
A selective but not totally specific inhibitor of ALOX12 reduced the growth response of cultured human endothelial cells to basic fibroblast growth factor and vascular endothelial growth factor (VEGF); this reduction was partially reversed by 12("S")-HETE; 12("S")-HETE also stimulates human prostate cell lines to produce VEGF. These results suggest that growth responses to the two growth factors involves their stimulation of 12("S")-HETE production by endothelial cells and therefore that ALOX12 may be a target for reducing the neo-vascularization that promotes arthritic and cancer diseases. 12("S")-HETE also dilates human coronary microcirculation arteries by activating these vessels' smooth muscle BKca Potassium channels and is therefore suggested to be an Endothelium-derived hyperpolarizing factor. Finally, a single nucleotide variant in the "ALOX12" gene (R261Q [3957 G>A]) has been associated with essential hypertension and elevation in the urinary excretion of 12("S")-HETE in humans and may be a contributing factor for to essential hypertension (see also 12-HETE#Blood pressure).
Placental growth factor
Placental growth factor is a protein that in humans is encoded by the "PGF" gene.
Insulin-like growth factor 2
Insulin-like growth factor 2 (IGF-2) is one of three protein hormones that share structural similarity to insulin. The MeSH definition reads: "A well-characterized neutral peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on somatotropin. It is believed to be a major fetal growth factor in contrast to Insulin-like growth factor 1, which is a major growth factor in adults".
Growth hormone
A number of factors are known to affect GH secretion, such as age, sex, diet, exercise, stress, and other hormones. Young adolescents secrete GH at the rate of about 700 μg/day, while healthy adults secrete GH at the rate of about 400 μg/day. Sleep deprivation generally suppresses GH release, particularly after early adulthood.
Insulin-like growth factor 1
IGF-1 is a hormone similar in molecular structure to insulin. It plays an important role in childhood growth and continues to have anabolic effects in adults. A synthetic analog of IGF-1, mecasermin, is used for the treatment of growth failure.
Human height
If not enough growth hormone is produced and/or secreted by the pituitary gland, then a patient with growth hormone deficiency can undergo treatment. This treatment involves the injection of pure growth hormone into thick tissue to promote growth.
Growth factor
The growth factor was first discovered by Rita Levi-Montalcini, which won her a Nobel Prize in Physiology or Medicine.
Breast development
Insulin, glucocorticoids such as cortisol (and by extension adrenocorticotropic hormone (ACTH)), and thyroid hormones such as thyroxine (and by extension thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH)) also play permissive but less well-understood/poorly-characterized roles in breast development during both puberty and pregnancy, and are required for full functional development. Leptin has also been found to be an important factor in mammary gland development, and has been found to promote mammary epithelial cell proliferation.
Dwarfism
Growth hormone deficiency (GHD) is a medical condition in which the body produces insufficient growth hormone. Growth hormone, also called somatotropin, is a polypeptide hormone which stimulates growth and cell reproduction. If this hormone is lacking, stunted or even halted growth may become apparent. Children with this disorder may grow slowly and puberty may be delayed by several years or indefinitely. Growth hormone deficiency has no single definite cause. It can be caused by mutations of specific genes, damage to the pituitary gland, Turner's syndrome, poor nutrition, or even stress (leading to psychogenic dwarfism). Laron syndrome (growth hormone insensitivity) is another cause. Those with growth hormone issues tend to be proportionate.
Michael O. Thorner
His work on human growth hormone was the basis of Merck's drug MK-677, which increases muscle mass in elderly adults and helps prevent frailty-related injuries. He was the chair of the National Institute on Aging Advisory Panel on Testosterone Replacement in Men (2000). In 2013, he received the highest award of the Endocrine Society, the Koch Medal.
Bovine somatotropin
IGF-1 is a hormone found in humans that is responsible for growth promotion, protein synthesis, and insulin actions over the lifecycle. The hormone has been shown to influence the growth of tumors in some studies and may be linked to the development of prostate, colorectal, breast, and other cancers.
Transgender hormone therapy (male-to-female)
Progesterone, a progestogen, is the other of the two major sex hormones in women. It is mainly involved in the regulation of the female reproductive system, the menstrual cycle, pregnancy, and lactation. The non-reproductive effects of progesterone are fairly insignificant. Unlike estrogens, progesterone is not known to be involved in the development of female secondary sexual characteristics, and hence is not believed to contribute to feminization in women. One area of particular interest in terms of the effects of progesterone in women is breast development. Estrogens are responsible for the development of the ductal and connective tissues of the breasts and the deposition of fat into the breasts during puberty in girls. Conversely, high levels of progesterone, in conjunction with other hormones such as prolactin, are responsible for the lobuloalveolar maturation of the mammary glands during pregnancy. This allows for lactation and breastfeeding after childbirth. Although progesterone causes the breasts to change during pregnancy, the breasts undergo involution and revert to their pre-pregnancy composition and size after the cessation of breastfeeding. Every pregnancy, lobuloalveolar maturation occurs again anew.
Xenoestrogen
The onset of puberty is characterized by increased levels of hypothalamic gonadotropin releasing hormone (GnRH). GnRH triggers the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary gland, which in turn causes the ovaries to respond and secrete estradiol. Increases in gonadal estrogen promote breast development, female fat distribution and skeletal growth. Adrenal androgen and gonadal androgen result in pubic and axillary hair. Peripheral precocious puberty caused by exogenous estrogens is evaluated by assessing decreased levels of gonadotrophins.
Oscar Riddle
In his time, Riddle was one of the top biologists in the United States. His research spanned endocrinology, the physiology of reproduction, animal pigmentation, and the nature and functional basis of sex. He is most remembered for his research into the major pituitary hormone prolactin. Riddle studied under Jacques Loeb, and he and his colleagues were the first to isolate prolactin, which was named by Riddle in 1932. Riddle discovered that prolactin injections inhibited gonad growth in males and produced maternal behavior in females. His research demonstrated that prolactin and other hormones of the frontal lobe are disintegrated by the enzyme trypsin. His work also showed that growth is a synergistic response to the hormones prolactin and thyrotropin. He earned a degree in law in 1933 and was featured on the cover of TIME in January 1939. Riddle retired in 1945.
Reproductive biology
Human reproductive biology is primarily controlled through hormones, which send signals to the human reproductive structures to influence growth and maturation. These hormones are secreted by endocrine glands, and spread to different tissues in the human body. In humans, the pituitary gland synthesizes hormones used to control the activity of endocrine glands.
Puberty
The hormone that dominates female development is an estrogen called estradiol. While estradiol promotes growth of the breasts and uterus, it is also the principal hormone driving the pubertal growth spurt and epiphyseal maturation and closure. Estradiol levels rise earlier and reach higher levels in women than in men.
Testosterone
The bones and the brain are two important tissues in humans where the primary effect of testosterone is by way of aromatization to estradiol. In the bones, estradiol accelerates ossification of cartilage into bone, leading to closure of the epiphyses and conclusion of growth. In the central nervous system, testosterone is aromatized to estradiol. Estradiol rather than testosterone serves as the most important feedback signal to the hypothalamus (especially affecting LH secretion). In many mammals, prenatal or perinatal "masculinization" of the sexually dimorphic areas of the brain by estradiol derived from testosterone programs later male sexual behavior.
Estrogen
Estrogens are responsible for both the pubertal growth spurt, which causes an acceleration in linear growth, and epiphyseal closure, which limits height and limb length, in both females and males. In addition, estrogens are responsible for bone maturation and maintenance of bone mineral density throughout life. Due to hypoestrogenism, the risk of osteoporosis increases during menopause.
Biotechnology in pharmaceutical manufacturing
Prior to the use of recombinant DNA technology to modify bacteria to produce human growth hormone, the hormone was manufactured by extraction from the pituitary glands of cadavers, as animal growth hormones have no therapeutic value in humans. Production of a single year's supply of human growth hormone required up to fifty pituitary glands, creating significant shortages of the hormone. In 1979, scientists at Genentech produced human growth hormone by inserting DNA coding for human growth hormone into a plasmid that was implanted in Escherichia coli bacteria. The gene that was inserted into the plasmid was created by reverse transcription of the mRNA found in pituitary glands to complementary DNA. HaeIII, a type of restriction enzyme which acts at restriction sites "in the 3' noncoding region" and at the 23rd codon in complementary DNA for human growth hormone, was used to produce "a DNA fragment of 551 base pairs which includes coding sequences for amino acids 24–191 of HGH." Then "a chemically synthesized DNA 'adaptor' fragment containing an ATG initiation codon..." was produced with the codons for the first through 23rd amino acids in human growth hormone. The "two DNA fragments... [were] combined to form a synthetic-natural 'hybrid' gene." The use of entirely synthetic methods of DNA production to produce a gene that would be translated to human growth hormone in escherichia coli would have been exceedingly laborious due to the significant length of the amino acid sequence in human growth hormone. However, if the cDNA reverse transcribed from the mRNA for human growth hormone were inserted directly into the plasmid inserted into the escherichia coli, the bacteria would translate regions of the gene that are not translated in humans, thereby producing a "pre-hormone containing an extra 26 amino acids" which might be difficult to remove.
NCAA banned substances
Human growth hormone is a naturally occurring hormone that is responsible for general body growth in both men and women. hGH helps the body protein while breaking down fat deposits. Too much hGH results in increased muscle mass. (Santella 45)
Somatotropin family
The Somatotropin family is a protein family whose titular representative is somatotropin, also known as growth hormone, a hormone that plays an important role in growth control. Other members include choriomammotropin (lactogen), its placental analogue; prolactin, which promotes lactation in the mammary gland, and placental prolactin-related proteins; proliferin and proliferin related protein; and somatolactin from various fishes. The 3D structure of bovine somatotropin has been predicted using a combination of heuristics and energy minimisation.
Wylie Vale
At the Salk Institute, Vale led efforts in identifying the group of hormones involved in human growth, reproduction and temperature. His group discovered, isolated and identified corticotropin-releasing hormone (CRF/CRH) in 1981 and growth hormone releasing factor (GHRF) in 1982.
Growth hormone
Prior to its production by recombinant DNA technology, growth hormone used to treat deficiencies was extracted from the pituitary glands of cadavers. Attempts to create a wholly synthetic HGH failed. Limited supplies of HGH resulted in the restriction of HGH therapy to the treatment of idiopathic short stature. Very limited clinical studies of growth hormone derived from an Old World monkey, the rhesus macaque, were conducted by John C. Beck and colleagues in Montreal, in the late 1950s. The study published in 1957, which was conducted on "a 13-year-old male with well-documented hypopituitarism secondary to a crainiophyaryngioma," found that: "Human and monkey growth hormone resulted in a significant enhancement of nitrogen storage ... (and) there was a retention of potassium, phosphorus, calcium, and sodium. ... There was a gain in body weight during both periods. ... There was a significant increase in urinary excretion of aldosterone during both periods of administration of growth hormone. This was most marked with the human growth hormone. ... Impairment of the glucose tolerance curve was evident after 10 days of administration of the human growth hormone. No change in glucose tolerance was demonstrable on the fifth day of administration of monkey growth hormone." The other study, published in 1958, was conducted on six people: the same subject as the Science paper; an 18-year-old male with statural and sexual retardation and a skeletal age of between 13 and 14 years; a 15-year-old female with well-documented hypopituitarism secondary to a craniopharyngioma; a 53-year-old female with carcinoma of the breast and widespread skeletal metastases; a 68-year-old female with advanced postmenopausal osteoporosis; and a healthy 24-year-old medical student without any clinical or laboratory evidence of systemic disease.
Growth hormone
The identification, purification and later synthesis of growth hormone is associated with Choh Hao Li. Genentech pioneered the first use of recombinant human growth hormone for human therapy in 1981.
American Academy of Anti-Aging Medicine
The American Academy of Anti-Aging Medicine was formed following a 1990 study on human growth hormone (hGH) that was published in the "New England Journal of Medicine". The study was performed by Daniel Rudman and colleagues at the Medical College of Wisconsin. Rudman had treated twelve men over 60 years of age with human growth hormone; after six months, these men had an increase in lean body mass and a decrease in adipose tissue mass when compared with a group of nine men who did not receive hormone. Members of the anti-aging movement have interpreted these results to support a role for growth hormone in slowing or reversing aging. A review in "The Journal of Urology" noted that this promotion of growth hormone as an anti-aging remedy is "arguably similar" to ideas that date back to the late 19th century, when the physiologist Charles-Édouard Brown-Séquard advocated rejuvenating hormone products prepared from animal testicles and stated that "the injections have taken 30 years off my life".
Neuroscience of sleep
The effect of sleep duration on somatic growth is not completely known. One study recorded growth, height, and weight, as correlated to parent-reported time in bed in 305 children over a period of nine years (age 1–10). It was found that "the variation of sleep duration among children does not seem to have an effect on growth." It is well established that slow-wave sleep affects growth hormone levels in adult men. During eight hours' sleep, Van Cauter, Leproult, and Plat found that the men with a high percentage of SWS (average 24%) also had high growth hormone secretion, while subjects with a low percentage of SWS (average 9%) had low growth hormone secretion.
C-fos-induced growth factor
C-fos-induced growth factor (FIGF) (or vascular endothelial growth factor D, VEGF-D) is a vascular endothelial growth factor that in humans is encoded by the "FIGF" gene.
Tabimorelin
Tabimorelin (INN) (developmental code name NN-703) is a drug which acts as a potent, orally-active agonist of the ghrelin/growth hormone secretagogue receptor (GHSR) and growth hormone secretagogue, mimicking the effects of the endogenous peptide agonist ghrelin as a stimulator of growth hormone (GH) release. It was one of the first GH secretagogues developed and is largely a modified polypeptide, but it is nevertheless orally-active "in vivo". Tabimorelin produced sustained increases in levels of GH and insulin-like growth factor 1 (IGF-1), along with smaller transient increases in levels of other hormones such as adrenocorticotropic hormone (ACTH), cortisol, and prolactin. However actual clinical effects in adults with growth hormone deficiency were limited, with only the most severely GH-deficient patients showing significant benefit, and tabimorelin was also found to act as a CYP3A4 inhibitor which could cause it to have undesirable interactions with other drugs.
Growth hormone deficiency
Cost of adult treatment in the UK is 3000-4000 GBP annually.When treated with GH, a severely deficient child will begin to grow faster within months. In the first year of treatment, the rate of growth may increase from half as fast as other children are growing to twice as fast (e.g., from 1 inch a year to 4 inches, or 2.5 cm to 10). Growth typically slows in subsequent years, but usually remains above normal so that over several years a child who had fallen far behind in his height may grow into the normal height range. Excess adipose tissue may be reduced.
Growth hormone secretagogue receptor
Growth hormone secretagogue receptor(GHS-R), also known as ghrelin receptor, is a G protein-coupled receptor that binds growth hormone secretagogues (GHSs), such as ghrelin, the "hunger hormone". The role of GHS-R is thought to be in regulating energy homeostasis and body weight. In the brain, they are most highly expressed in the hypothalamus, specifically the ventromedial nucleus and arcuate nucleus. GSH-Rs are also expressed in other areas of the brain, including the ventral tegmental area, hippocampus, and substantia nigra. Outside the central nervous system, too, GSH-Rs are also found in the liver, in skeletal muscle, and even in the heart.
Human penis size
There are certain genes, like homeobox (Hox a and d) genes, which may have a role in regulating penis size. In humans, the AR gene located on the X chromosome at Xq11-12 which may determine the penis size. The SRY gene located on the Y chromosome may have a role to play. Variance in size can often be attributed to "de novo" mutations. Deficiency of pituitary growth hormone or gonadotropins or mild degrees of androgen insensitivity can cause small penis size in males and can be addressed with growth hormone or testosterone treatment in early childhood.
Trophic hormone
Trophic hormone is a hormone that has a growth effect, hyperplasia or hypertrophy, on the tissue it is stimulating. The term "trophic" is from Ancient Greek τροφικός ("trophikós") meaning "pertaining to food or nourishment", here used to mean "growth"; this is the same origin as "atrophy." This should not be confused with "tropic," as in the similar-sounding tropic hormone – the words and concepts are both unrelated.
Human height
Humans grow fastest (other than in the womb) as infants and toddlers, rapidly declining from a maximum at birth to roughly age 2, tapering to a slowly declining rate, and then during the pubertal growth spurt, a rapid rise to a second maximum (at around 11–12 years for female, and 13–14 years for male), followed by a steady decline to zero. On average, female growth speed trails off to zero at about 15 or 16 years, whereas the male curve continues for approximately 3 more years, going to zero at about 18–19. These are also critical periods where stressors such as malnutrition (or even severe child neglect) have the greatest effect.
Adolescence
The adolescent growth spurt is a rapid increase in the individual's height and weight during puberty resulting from the simultaneous release of growth hormones, thyroid hormones, and androgens. Males experience their growth spurt about two years later, on average, than females. During their peak height velocity (the time of most rapid growth), adolescents grow at a growth rate nearly identical to that of a toddler—about 4 inches (10.3 cm) a year for males and 3.5 inches (9 cm) for females. In addition to changes in height, adolescents also experience a significant increase in weight (Marshall, 1978). The weight gained during adolescence constitutes nearly half of one's adult body weight. Teenage and early adult males may continue to gain natural muscle growth even after puberty.
Insulin-like growth factor 1 receptor
The insulin-like growth factor 1 (IGF-1) receptor is a protein found on the surface of human cells. It is a transmembrane receptor that is activated by a hormone called insulin-like growth factor 1 (IGF-1) and by a related hormone called IGF-2. It belongs to the large class of tyrosine kinase receptors. This receptor mediates the effects of IGF-1, which is a polypeptide protein hormone similar in molecular structure to insulin. IGF-1 plays an important role in growth and continues to have anabolic effects in adults – meaning that it can induce hypertrophy of skeletal muscle and other target tissues. Mice lacking the IGF-1 receptor die late in development, and show a dramatic reduction in body mass, testifying to the strong growth-promoting effect of this receptor. Mice carrying only one functional copy of IGF-1R are normal, but exhibit a ~15% decrease in body mass.
Bone resorption
Growth hormone is an important regulator of bone growth and remodeling in adults, and it acts via insulin-like growth factor I (IGF1) to stimulate osteoblastic differentiation. Chronic alcoholism decreases the levels of IGF1, which suppresses the ability of GH to increase bone mineral density.