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

Abstract

Follicle-stimulating hormone (FSH) stimulates aromatase activity of immature rat Sertoli cells cultured in vitro in the presence of an androgen substrate, a phenomenon that can be used to measure FSH bioactivity. 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 concentrations of serum from humans, monkeys, rats, hamsters, and mice gave a dose-dependent stimulation of estradiol production parallel to the response obtained with FSH standard. Serum from these species and from rabbits also had a characteristic morphological effect on the cells, to produce a fibroblast-like aspect and clumping. This effect was dose-dependent, was increased by the addition of FSH, and was eliminated by heating the sera at 56° for 30 min prior to incubation with the cells. Clumping did not interfere with the aromatase activity of Sertoli cells and did not cause the cellular response to deviate from parallelism with the standard curve. Heat treatment of FSH standard and serum samples did not significantly change the aromatase activity. FSH bioactivity 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 species without any preliminary treatment of the serum samples.