Differential Control of Luteinizing Hormone and Follicle-Stimulating Hormone Secretion by Androgens in Rat Pituitary Cells in Culture: Functional Diversity of Subpopulations Separated by Unit Gravity Sedimentation*

Abstract

Monolayer cultures of dispersed pituitary cells derived from 14-day-old female rats were treated for 70 h with nanomolar concentrations of testosterone (T) or 5α-dihydrotestosterone (DHT), and the effect of these hormones on LHRHstimulated FSH and LH release was tested. The effect of androgen treatment on FSH release depended critically on the concentration of LHRH; FSH release either was slightly stimulated, markedly depressed, or not affected at all. In contrast, LH release was profoundly inhibited, except at very high concentrations of LHRH. Various cell populations, separated according to size and density by gradient sedimentation at unit gravity, did not respond equally to DHT treatment. Inhibition of FSH release did hot occur in all gonadotrophs and was seen only at critical concentrations of LHRH. Stimulation of FSH release, observed at low concentrations of LHRH, was found only in the fraction with the largest gonadotrophs; in the latter there was no concomitant change in LH release. FSH release from small gonadotrophs remained unchanged, but LH release was depressed. The present observations clearly show that LHRH can provoke selective FSH release without any change in LH release and that LH secretion can be inhibited without a concomitant fall in FSH. It is suggested that such independent control is mediated through separate subpopulations of functionally diverse gonadotrophs. (Endocrinology106: 724, 1980)