HCG: Human Chorionic Gonadotropin Research Guide

Human Chorionic Gonadotropin (hCG) is a glycoprotein hormone composed of 237 amino acids with a molecular mass of 36.7 kDa. It plays crucial roles in reproductive research and hormonal studies. - α-subunit: 92 amino acids (14.5 kDa) — identical to LH, FSH, and TSH - β-subunit: 145 amino acids (22.2 kDa) — unique to hCG The β-subunit contains a Carboxy Terminus Peptide (β-CTP) giving hCG a much longer half-life (24-36 hours) compared to LH (25-30 minutes). Four major forms exist: 1. Regular hCG — standard form 2. Hyperglycosylated hCG (hCG-H) — specialized variant 3. Free β-subunit — independent β-chain 4. Pituitary hCG — sulfated variant hCG binds to the LH/CG receptor (LHCGR) on target cells, activating: - Protein Kinase A (PKA) — promotes steroidogenesis - Protein Kinase C (PKC) — regulates cell proliferation - Smad2 signaling — involved in differentiation - Stimulates luteal cells to produce progesterone - Maintains hormonal support - Regulates downstream androgen produ