HCG

Human chorionic gonadotropin (hCG) is a glycoprotein hormone consisting of alpha and beta subunits. The alpha subunit is shared with LH, FSH, and TSH; the beta subunit is unique to hCG and confers receptor specificity. hCG binds the LH/hCG receptor (LHCGR) with higher affinity and a much longer half-life than LH itself, making it the pharmacological equivalent of LH in research contexts where sustained receptor stimulation is needed.

In reproductive biology, hCG's endogenous role is associated with pregnancy maintenance -- it is produced by trophoblast cells after implantation and signals to the corpus luteum to maintain progesterone production during early pregnancy. Its presence in urine forms the basis of pregnancy tests. In research models, hCG is studied as an LH-surge mimic in ovulation research, as a Leydig-cell stimulus in testosterone-production studies, as a tool for assessing Leydig cell function, and in models of gonadal development.

For research involving the male HPG axis, hCG provides an LH agonist effect: it is studied for its role in stimulating Leydig cells in testosterone-production research models without requiring pituitary LH secretion. This makes it useful for studying testosterone production independently of pituitary-hypothalamic function in model systems, and for maintaining testicular function in research protocols that suppress LH (such as GnRH agonist or antagonist studies).

Specifications

Storage

Store at 2-8°C (refrigerator). As a glycoprotein, hCG should not be frozen repeatedly -- store lyophilized form refrigerated, not frozen. After reconstitution, use within 28 days at 2-8°C. Do not shake; gently swirl to dissolve.

HCG is supplied for laboratory research use only. Not approved for unsanctioned human use. Handle in compliance with institutional biosafety guidelines.