Autoregulation of androgen production in a primary culture of rat testicular cells

Abstract

Studies on hypophysectomized rats have suggested that testicular androgen production may be locally autoregulated via an ultra-short loop negative feedback mechanism^1,2. Conclusive demonstration of this phenomenon in vitro has been hampered by lack of a functional testicular cell culture and the use of native androgens which are subject to extensive metabolism and interfere with measurements of endogenous androgens. We have now used a recently developed primary culture of rat testicular cells³ and synthetic steroids, and report that a synthetic androgen (R1881)⁴ decreases, whereas a synthetic anti-androgen (cyproterone acetate)⁵ increases, the gonadotropin-stimulated accumulation of testosterone in vitro. Furthermore, cyproterone acetate antagonized the inhibitory effect of R1881 on the accumulation of testosterone. In contrast, R5020 (ref. 6), a highly specific and metabolically stable progestin, did not affect the gonadotropin-stimulated accumulation of testosterone. These findings are the first in vitro demonstration of local autoregulation of testicular androgen production and suggest that the intratesticular negative feedback action of androgens may be mediated by specific testicular androgen receptors.