Description
HCG is a glycoprotein hormone naturally produced by the placenta in early pregnancy, where it plays a critical role in maintaining hormone production during the first trimester. Its close structural and functional similarity to luteinising hormone (LH) — the pituitary signal that triggers testosterone production in men and ovulation in women — has made it one of the most widely used tool compounds in reproductive endocrinology research.
What the research has found
• Studies in Leydig cells (the testosterone-producing cells of the testes) demonstrated that HCG binds the LH receptor and activates a cascade of enzyme expression that drives the conversion of cholesterol to testosterone. This makes it an invaluable model compound for studying the testosterone biosynthesis pathway (Ziecik et al., 2007)
• Research characterising the structural differences between HCG and LH identified a 24-amino acid C-terminal extension on the HCG beta subunit that significantly extends its circulation time compared to LH — explaining why HCG can sustain corpus luteum function across weeks of early pregnancy where LH’s short half-life could not (Lapthorn et al., 1994)
• Beyond reproductive tissue, research identified LH/HCG receptors in the thyroid, adrenal gland, and uterine endometrium, opening research directions into the non-reproductive roles of HCG signalling across different tissue types (Cole, 2012)
• Studies have mapped both the classic cAMP-dependent signalling pathway and additional downstream cascades activated by HCG receptor binding, revealing a more complex signalling biology than initially characterised (Cole, 2012)
For research use only. Not intended for use in humans or animals.
References
Cole, L. A. (2012). https://pubmed.ncbi.nlm.nih.gov/22046241/
Lapthorn, A. J., et al. (1994). https://pubmed.ncbi.nlm.nih.gov/8205136/
Ziecik, A. J., et al. (2007). https://pubmed.ncbi.nlm.nih.gov/11330789/
