Direct inhibition of testicular androgen biosynthesis by arginine-vasopressin: mediation through pressor-selective testicular recognition sites.
We have observed that arginine vasopressin (AVP) and related neurohypophysial hormones exert direct inhibition of testicular androgen biosynthesis in vitro. In this report, the functional identity of the putative testicular recognition sites mediating the antigonadal activity of the neurohypophysial hormones was investigated. Pressor-selective (but not antidiuretic- or oxytocic-selective) agonists of neurohypophysial hormones exerted a dose-dependent inhibition of the hCG-stimulated accumulation of testosterone by cultured rat testicular cells. In addition, potent pressor (but not oxytocic) antagonists brought about a dose-dependent blockage of the AVP-induced inhibition of testicular androgen biosynthesis. Thus, the antigonadal activity of neurohypophysial hormones is mediated by specific testicular recognition sites similar to those mediating the pressor actions of these neuropeptides but distinct from those involved in their antidiuretic or oxytocic effects.
D000728:Androgens / Q000096:biosynthesis*; D000818:Animals; D001127:Arginine Vasopressin / Q000031:analogs & derivatives / Q000494:pharmacology*; D007016:Hypophysectomy; D008297:Male; D010121:Oxytocin / Q000494:pharmacology; D051381:Rats; D013329:Structure-Activity Relationship; D013737:Testis / Q000187:drug effects / Q000378:metabolism*
D000728:Androgens; D001127:Arginine Vasopressin; D010121:Oxytocin