FSH BIOACTIVITY IN COMMERCIAL PREPARATIONS OF GONADOTROPINS

During the past 2 decades, commercial preparations of FSH have been ex tensively used to superovulate cattle. The problems that have been enc ountered in superovulation of cattle include high variability in the o vulation rate and subsequent yield of viable embryos. The lack of pred ictability in superovulatory trials has been attributed to difficultie s in standardizing the potency, of commercial FSH preparations. Tradit ionally, FSH potency has been tested in bioassays that utilize specifi c responses in whole animals or primary cell cultures. Whole animal bi oassays lack sensitivity, while primary cell culture bioassays, which use fresh cells, have inherent variability within each preparation. An FSK bioassay that employed a stable chimeric cell line expressing the human FSH-R was used to provide an accurate measurement of FSH bioact ivity. The hormonal potency of 2 commercial preparations of FSH used t o superovulate cattle was determined using FSH immune-and bioassays. C ommercial FSH preparations differed in potency. One commercial product , prepared in 4 different years, showed no difference in the immunoact ive levels of FSH. In the same product stored under identical conditio ns, FSH bioactivity varied from year to year. There was variability in FSH bioactivity both between and within commercial products. The lack of correlation between bioactivity and immunoactivity of commercial F SH preparations may explain, in part, the variability observed in supe rovulation of cattle. (C) 1998 by Elsevier Science Inc.