Hypogonadotropic hypogonadism (HH),  is due to problems with either the hypothalamus or pituitary gland affecting the hypothalamic-pituitary-gonadal axis (HPG axis). Hypothalamic disorders result from a deficiency in the release of gonadotropic releasing hormone (GnRH), while pituitary gland disorders are due to a deficiency in the release of gonadotropins from the anterior pituitary. GnRH is the central regulator in reproductive function and sexual development via the HPG axis. GnRH is released by GnRH neurons, which are hypothalamic neuroendocrine cells, into the hypophyseal portal system acting on gonadotrophs in the anterior pituitary. The release of gonadotropins, LH and FSH, act on the gonads for the development and maintenance of proper adult reproductive physiology. LH acts on Leydig cells in the male testes and theca cells in the female. FSH acts on Sertoli cells in the male and follicular cells in the female. Combined this causes the secretion of gonadal sex steroids and the initiation of folliculogenesis and spermatogenesis. The production of sex steroids forms a negative feedback loop acting on both the anterior pituitary and hypothalamus causing a pulsatile secretion of GnRH. GnRH neurons lack sex steroid receptors and mediators such as kisspeptin stimulate GnRH neurons for pulsatile secretion of GnRH. Types
There are two subtypes of HH, congenital HH (CHH) and acquired HH (AHH). CHH is due to genetic abnormalities resulting in non-functional GnRH secreting neurons or gonadotropic cell dysfunction in the anterior pituitary. CHH is divided into 2 subtypes depending on the condition of the olfactory system, anosmic HH (Kallman syndrome) and normosmic HH.
Antisialagogues are drugs or substances that decrease the flow rate of saliva and their effect is opposite to that of sialagogues. Their origin may be both natural and synthetic. Anticholinergics generally have antisialagogue effects, and most produce some level of sedation, both being advantageous in surgical procedures. Classic antisialagogues include:

atropine,
opium,
alkalies,
belladonna,
hyoscyamus,
stramonium,
tobacco in excess,
all nauseous or insipid substances. == References ==