Regulation of testicular human chorionic gonadotrophin binding in prolactin-deficient Snell dwarf mice.
The regulation of binding of 125 I-labelled human chorionic gonadotrophin (hCG) to testis was studied in mutant mice with congenital deficiency of prolactin (dw/dw), in mice with prolactin deficiency induced by treatment with bromocriptine and in normal untreated mice. After injection of hCG, normal mice showed a dose-related decrease in testicular hCG binding and subsequent recovery from down-regulation, similar to previous findings in the rat. Mice with congenital prolactin deficiency had a similar dose-response curve of receptor loss after hCG administration, but recovered from down-regulation faster than the normal mice. Induction of prolactin deficiency with bromocriptine prevented down-regulation of hCG binding. The differential effects of congenital and drug-induced prolactin deficiency could be related to a difference in the duration of the deficiency or to its severity. However, this difference could also suggest direct effects of the dw mutation and/or bromocriptine on the Leydig cells.
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D006063:Chorionic Gonadotropin / Q000378:metabolism* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D011388:Prolactin / Q000172:deficiency*; D013737:Testis / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000097:blood
D006063:Chorionic Gonadotropin; D001971:Bromocriptine; D013739:Testosterone; D011388:Prolactin