IN-VITRO SERTOLI-CELL BIOASSAY OF FOLLICLE-STIMULATING-HORMONE (FSH) - SERUM FROM DIFFERENT ANIMAL SPECIES ALTERS THE MORPHOLOGY OF RAT SERTOLI CELLS WITHOUT AFFECTING THEIR RESPONSE TO FSH

Follicle-stimulating hormone (FSH) stimulates aromatase activity of im mature rat Sertoli cells cultured in vitro in the presence of an andro gen substrate, a phenomenon that can be used to measure FSH bioactivit y. This paper analyzes the effects of sera from various animal species on both aromatase activity and morphological aspects of cultured rat Sertoli cells. Treatment of Sertoli cells with increasing concentratio ns of serum from humans, monkeys, rats, hamsters, and mice gave a dose -dependent stimulation of estradiol production parallel to the respons e obtained with FSH standard. Serum from these species and from rabbit s also had a characteristic morphological effect on the cells, to prod uce a fibroblast-like aspect and clumping. This effect was dose-depend ent, was increased by the addition of FSH, and was eliminated by heati ng the sera at 56 degrees for 30 min prior to incubation with the cell s. Clumping did not interfere with the aromatase activity of Sertoli c ells and did not cause the cellular response to deviate from paralleli sm with the standard curve. Heat treatment of FSH standard and serum s amples did not significantly change the aromatase activity. FSH bioact ivity could be measured accurately in intact and castrated monkeys. It is concluded that the Sertoli cell aromatase bioassay can be applied directly to the measurement of serum bioactive FSH in several animal s pecies without any preliminary treatment of the serum samples. (C) 199 4 Academic Press, Inc.