Follicle-Stimulating Hormone and Testosterone Independently Increase the Production of Androgen- Binding Protein by Sertoli Cells in Culture*

Dose-response curves were obtained for the production of androgen-binding protein (ABP) by Sertoli cells prepared from testes of 20-day-old rats and treated in culture with either FSH or testosterone (T). FSH stimulated ABP production by up to 3.5 times control levels. For NIH-FSH-S11, the ED50 was 3 ng/ml, and for highly purified ovine FSH, the ED50 was 0.066 ng/ml. Addition of T produced a stimulation of up to 3 times control levels; half-maximal response was obtained at a dose of 4 nM. The presence of small numbers of contaminating Leydig cells in some preparations resulted in production of endogenous T, especially when high doses of NIH-FSH, which contains some LH, were employed. A modified preparation method involving exposure of the cells to distilled water reduced the endogenous T production to low levels. In cultures of cells prepared in this way, addition of the antiandrogen cyproterone acetate at a concentration high enough to reduce fractional occupancy of androgen receptors by endogenous T to 0.014 or less had no effect on the stimulation by FSH of ABP production in the cultures. In contrast, cyproterone acetate inhibited stimulation by T of ABP production. We conclude that FSH and T act independently on Sertoli cells from immature rats to increase the secretion of ABP.