title: A sensitive and specific in vitro bioassay method for the measurement of follicle-stimulating hormone activity.
abstract: An in vitro bioassay method for hFSH is presented. The method is based on the principles previously described by Dorrington et al. (1976b) and involves the assay of oestradiol produced from 19-hydroxyandrostenedione by dispersed Sertoli cells of 10-day old rats when cultured in the presence of graded doses of FSH. Using the 1st International Reference Preparation for human pituitary gonadotrophins (FSH and LH/ICSH) for bioassay (code no. 69/104) as standard, the useful range of the method is from 0.5 to 32 mIU/chamber (2 to 128 mIU/ml). The sensitivity of the method is 0.5 mIU/chamger. The mean index of precision (lambda) obtained from 16 multiple assays over 2 or 3 dose levels was 0.084. Parallelism was obtained between the 69/104 preparation and all preparations under study. The practicability of the proposed assay method is such that 15 preparations at 3 dose levels can be assayed by one person in 3 days. The specificity of the assay was investigated by determining the FSH activity in the following preparations: hFSH alpha- and beta-subunits, hLH, hCG, hTSH, ACTH, human growth hormone (hGH) human prolactin (hPRL) and luteinizing hormone-releasing hormone (LH-RH). The ACTH, hGH, hPRL and LH-RH preparations studied showed no detectable FSH activity in the assay. In the remaining preparations very low levels of FSH activity were found, corresponding to 0.004 to 0.6% of the weight of these preparations when compared with a highly purified hFSH preparation, suggesting that the method is specific for FSH. The possible synergistic or antagonistic influence of the above preparations when assayed in the presence of the 69/104 preparation was also assessed. No evidence of a synergistic or antogonistic effect was found. The assay of the hFSH potencies of a limited number of hFSH preparations of varying purity by the proposed in vitro bioassay, an hFSH radioreceptor method and an hFSH specific radioimmunoassay technique revealed that - although the relationship of the various potencies obtained with each method showed a close agreement - the bioassays yielded the highest potency estimates, and the radioimmunoassays the lowest ones. Since the proposed bioassay method is sensitive and considered to be specific for hFSH activity, it provides a suitable basis for the assessment of the specificity of other in vitro methods (radioreceptor and radioimmunoassay) currently used for detecting low levels of FSH activity.
mesh_terms: D000367:Age Factors; D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002452:Cell Count; D002478:Cells, Cultured; D003470:Culture Media; D004958:Estradiol / Q000096:biosynthesis; D005069:Evaluation Studies as Topic; D005640:Follicle Stimulating Hormone / Q000032:analysis*; D066298:In Vitro Techniques; D007202:Indicators and Reagents; D007986:Luteinizing Hormone / Q000032:analysis; D008297:Male; D011863:Radioimmunoassay; D011869:Radioligand Assay; D051381:Rats; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism*
chemical_list: D003470:Culture Media; D007202:Indicators and Reagents; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone