Synthesis of estradiol-17 beta by Sertoli cells in culture: stimulation by FSH and dibutyryl cyclic AMP.

Sertoli cells isolated from the testes of 18 to 20-day old rats synthesize estradiol-17 beta when grown in primary culture in the presence of testosterone (5 X 10(-7) M). After an initial lag phase of about 2 hours, follicle-stimulating hormone (FSH) stimulates synthesis of estradiol up to 50-fold, synthesis being approximately linear for 24 hours when medium is changed every 2-6 hours. Luteinizing hormone (LH) causes only a marginal stimulation, at concentrations consistent with contamination with FSH. Dibutyryl cyclic 3',5'-adenosine monophosphate (dbcAMP) (10(-4)M) mimicks the effect of FSH. No significant synthesis occurs in the absence of steroid substrate or in the presence of pregnenolone (5 X 10(-7) M). When cells are pre-incubated for 24 hours with FSH in the absence of testosterone, addition of testosterone results in an immediated increase in estradiol synthesis without a lag phase, suggesting that FSH or dbcAMP are capable of inducing the conditions necessary for stimulation in the absence of testosterone. These observations provide the first direct evidence of estradiol-17 beta synthesis by Sertoli cells from normal animals, and offer evidence that synthesis of this steroid is regulated at the level of the aromatizing enzyme system by FSH and cyclic AMP.