English
General description
Chorionic gonadotropin human (CGA or hCG) is a heterodimer and belongs to the cystine knot growth factor superfamily. It exists as six variants namely hCGn, hCGβ, hCGβn, hCGβcf and hCGα including hCG.[1] CGA is mapped to human chromosome 6q14.3.[2] hCG comprises of α and β chain.[3]
Glycoprotein hormone consisting of a 92-amino acid α-chain which is identical to that of LH, FSH, and TSH; and a distinct 149-amino acid β-chain. Produced by chorionic tissue and responsible for maintaining the corpus luteum during early pregnancy. Also produced by trophoblast cell neoplasms, which are marked by elevated free hCG β-chains and hyperglycosylated hCG.
Application
Chorionic gonadotropin human has been used:
to induce oocyte maturation in cultured follicles[4]
along with pregnant mare serum gonadotropin (PMSG) to induce superovulation in mice[5]
as medium component for fetal testes culture to aid steroidogenic responsiveness[6]
Biochem/physiol Actions
Elevated levels of hCG is observed in trophoblastic cancer.[7] hCG levels are indicators of pregnancy and β subunit is majorly present in urine samples.[8] hCG isoform detection is useful in the diagnosis and management of trophoblastic related diseases including carcinomas.[3]
Preparation Note
When reconstituted with water to a concentration of 1,000 IU/mL, the vial will also contain 0.02 M sodium phosphate buffer (pH approx. 7.2) and 20 mg/mL of mannitol.
Analysis Note
The calculated value is based on the USP method for human Chorionic Gonadotrophin, to meet 5,000 IU per vial, with a tolerance of not less than 80.0% and not more than 125.0% of the potency stated.
