A new reference preparation of human chorionic gonadotrophin and its subunits.

The establishment of CR119 human chorionic gonadotropin (HCG), CR119 HCGalpha, and CR119 HCGbeta(3) as reference preparations for the immunoassay of HCG and its subunits by the WHO Expert Committee on Biological Standardization is reported. The interstitial cell stimulating activity of CR119 HCG is 13,450 IU/mg and has proportional in vivo stimulatory activities for thyroid stimulating and follicle stimulating activities. The potencies of these activities for subunit preparations are uniformly less than .02 in relation to the undissociated hormone, and are recoverable in amounts approximately 75% of the total upon recombination. Each preparation has chemical, physical, and antigenic properties which are consistent with those reported for equally pure preparations.