Scientific Reference
HCG (Human Chorionic Gonadotropin)
Evidence profile: Controlled human evidence
Human chorionic gonadotropin, or hCG, is a glycoprotein hormone built from two non-covalently joined subunits, alpha and beta. The 92-residue alpha subunit is shared with luteinising hormone (LH), follicle-stimulating hormone and thyroid-stimulating hormone; the 145-residue beta subunit is specific to hCG and closely related to the beta subunit of LH. It is made mainly by trophoblast cells of the placenta, and its physiological role in early pregnancy is to sustain progesterone output from the corpus luteum. Heavy and variable glycosylation means that preparations from different sources are not chemically identical. It has been studied in receptor pharmacology, in gonadal cell and animal models of steroid synthesis, and in human endocrine research.
Mechanism of Action
hCG binds the luteinising hormone/choriogonadotropin receptor (LHCGR), a G protein-coupled receptor that it shares with LH. Receptor activation couples mainly to Gs, raising cyclic AMP and activating protein kinase A; at high hormone concentrations, Gq signalling has also been reported. In Leydig cells of the testis and in theca and luteal cells of the ovary, this signalling has been reported to raise levels of the steroidogenic acute regulatory protein (StAR) and of cholesterol side-chain cleavage enzyme, which control the first steps of steroid synthesis. The hCG beta subunit differs from that of LH by a C-terminal extension carrying O-linked sugar chains, a feature associated with its longer persistence 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