Bioassays of follicle stimulating hormone.

With the availability of these highly sensitive in vitro assays, measurement of bio-FSH in serum and urine becomes possible. Clinical studies have been done to investigate the role of bioactive FSH in different physiological and pathological conditions. There are however problems with these assays. All the assays required cell-culture facility and technique. In general they are technically demanding, expensive, and cumbersome. Both the GAB and SAB will take 5 working days for a technician to process 15-20 samples at multiple dilutions. Both assays rely on primary cultures of cells. Different pituitary FSH standards had been used for the validation of these biological assays. It had been previously demonstrated that pituitary and urinary gonadotropin preparations and standards exhibit different B/I ratios because of the marked heterogeneity of the gonadotropins. Comparing samples with standards of varying B/I ratios and bio-FSH activity makes the data difficult to interpret. In addition, in the GAB, rat FSH (FSH-I-6) and ovine FSH (NIH-S-15) are equipotent, but in the in vivo Steelman-Pohley assay, rat FSH is 5 times more potent than the ovine preparation. Similarly for the SAB, the NIH-hFSH-3 preparation was more potent than the NIH-hFSH-2 preparation, although the reverse was the case when biopotencies were stimulated by the Steelman-Pohley assays. This clearly demonstrates that both the GAB and SAB are in vitro bioassays and do not fully reflect in vivo activity.(ABSTRACT TRUNCATED AT 250 WORDS)