Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantation. The presence of hCG is detected in some pregnancy tests (HCG pregnancy strip tests). Some cancerous tumors produce this hormone; therefore, elevated levels measured when the patient is not pregnant may lead to a cancer diagnosis and, if high enough, paraneoplastic syndromes, however, it is not known whether this production is a contributing cause, or an effect of carcinogenesis. The pituitary analog of hCG, known as luteinizing hormone (LH), is produced in the pituitary gland of males and females of all ages.Various endogenous forms of hCG exist. The measurement of these diverse forms is used in the diagnosis of pregnancy and a variety of disease states. Preparations of hCG from various sources have also been used therapeutically, by both medicine and quackery. As of December 6, 2011, the United States Food and Drug Administration has prohibited the sale of "homeopathic" and over-the-counter hCG diet products and declared them fraudulent and illegal.Beta-hCG is initially secreted by the syncytiotrophoblast. Structure
Human chorionic gonadotropin is a glycoprotein composed of 237 amino acids with a molecular mass of 36.7 kDa, approximately 14.5kDa αhCG and 22.2kDa βhCG.It is heterodimeric, with an α (alpha) subunit identical to that of luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), and β (beta) subunit that is unique to hCG. The α (alpha) subunit is 92 amino acids long.
Others have argued that a hCG-laced vaccine could not possibly be used for sterilization, since the effects of the anti-fertility vaccines are reversible (requiring booster doses to maintain infertility) and a non-conjugated vaccine is likely to be ineffective. Finally, independent testing of the tetanus vaccine by Kenyas health authorities revealed no traces of the human chorionic gonadotropin hormone. See also
Equine chorionic gonadotropin
Gonadotropin preparations
Human placental lactogen
Triple test - a screening test in pregnancy
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References
External links
Chorionic+Gonadotropin at the US National Library of Medicine Medical Subject Headings (MeSH)
History of pregnancy test (NIH)