General description
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 in the biological validation of urinary testosterone (UTM) and urinary estradiol metabolites (UEM) EIA and superovulation.
Biochem/physiol Actions
Human chorionic gondadotropin (hCG) may be used as an alternative to PMSG to induce ovulation in laboratory animals. When hCG was injected into laboratory animals via intravenous (i.v.), intraperitoneal (i.p.), or subcutaneous (s.c.) methodstet, the effective dose values for 50% of the animals (ED50) per animal and per body weight (kg) in parenthesis were as follows:
Mice: i.v. 0.2 (7.7) I.U.; i.p. 0.3 (11.5) I.U.; s.c. 0.7 (26.9) I.U.
Syrian hamsters: i.v. 1.0 (9.5) I.U.; i.p. 1.8 (17.1) I.U.; s.c. 2.6 (24.8) I.U.
Rats: i.v. 1.3 (4.6) I.U.; i.p. 3.5 (12.3) I.U.; s.c.7.5 (26.3) I.U.
Using PMSG, the ED50 values per animal and per body weight (kg) in parenthesis were as follows:
Mice: i.v. 0.8 (30.8) I.U.; i.p. 2.0 (76.9) I.U.; s.c. 2.8 (107.7) I.U
Syrian hamsters: i.v., 3.6 (34.3) I.U.; i. p., 8.0 (76.2) I.U.; s.c., 13.2 (125.7) I.U.
Rats: i.v., 6.0 (76.8) I.U.; i p., 20.8 (73.0) I.U.; s.c., 76.8 (269.5) I.U.
Reconstitution
When reconstituted with water to a concentration of 1,000 IU/mL, the vial will also contain 0.1 M sodium phosphate buffer (pH approx. 7.2) and 100 mg/mL of mannitol.
Analysis Note
The calculated value is based on the USP method for human Chorionic Gonadotrophin, to meet 2,500 IU per vial, with a tolerance of not less than 80.0% and not more than 125.0% of the potency stated.