Scientific Reference
HCG (Human Chorionic Gonadotropin)
Evidence profile: Controlled human evidence
In early pregnancy hCG's job is to keep the corpus luteum producing progesterone, and it is made for that purpose mainly by the placenta's trophoblast cells. Structurally it is a glycoprotein hormone of two subunits held together without a covalent bond: a 92-residue alpha subunit shared with luteinising hormone, follicle-stimulating hormone and thyroid-stimulating hormone, and a 145-residue beta subunit unique to hCG and closely related to LH's. Glycosylation is heavy and variable, with the consequence that preparations from different sources are not chemically identical to one another. The research literature covers receptor pharmacology, gonadal cell and animal models of steroid synthesis, and human endocrine studies.
Mechanism of Action
hCG and LH share a receptor, the luteinising hormone/choriogonadotropin receptor, a G protein-coupled receptor. Activation couples mainly to Gs, lifting cyclic AMP and activating protein kinase A; Gq signalling has also been reported at high hormone concentrations. In testicular Leydig cells and in ovarian theca and luteal cells, that signalling has been reported to raise steroidogenic acute regulatory protein and cholesterol side-chain cleavage enzyme, the two controls on the opening steps of steroid synthesis. One structural difference from LH matters here: hCG's beta subunit carries a C-terminal extension bearing O-linked sugar chains, a feature associated with how much longer it persists in the circulation.
Molecular Information
- Type: Glycoprotein hormone (heterodimer)
Published Research
Clomiphene citrate and human chorionic gonadotropin are both effective in restoring testosterone in hypogonadism: a short-course randomized study
Habous M et al. · BJU international · 2018 · Clinical
PMID 29772111 — View on PubMedLate-onset hypogonadism: the advantages of treatment with human chorionic gonadotropin rather than testosterone
La Vignera S et al. · The aging male : the official journal of the International Society for the Study of the Aging Male · 2016 · Clinical
PMID 26488941 — View on PubMedGonadotropins for pubertal induction in males with hypogonadotropic hypogonadism: systematic review and meta-analysis
Alexander EC et al. · European journal of endocrinology · 2024 · Review
PMID 38128110 — View on PubMedA combined analysis of data to identify predictive factors for spermatogenesis in men with hypogonadotropic hypogonadism treated with recombinant human follicle-stimulating hormone and human chorionic gonadotropin
Warne DW et al. · Fertility and sterility · 2009 · Review
PMID 18930225 — View on PubMed