Dopamine regulation of testicular activity in intact and hypophysectomized frogs, Rana esculenta.
In intact frogs, both GnRHA and L-dopa were able to increase testicular and plasma androgen levels and to induce spermiation. The dopamine antagonist pimozide inhibited both the effects of L-dopa but not those of GnRHa. Hypophysectomy reduced androgen levels, but spermiation was still induced by both GnRHa and L-dopa, suggesting that these agents can directly influence the testis through a route not involving the pars distalis. Again, pimozide antagonised spermiation induced by L-dopa but not that induced by GnRHa.
Minucci
S
S
Dipartimento di Fisiologia Umana e Funzioni Biologiche Integrate F. Bottazzi, Facoltà di Medicina e Chirurgia, Università di Napoli, Italy.
Fasano
S
S
D'Antonio
M
M
Pierantoni
R
R
D000728:Androgens / Q000097:blood; D000818:Animals; D002064:Buserelin / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D007016:Hypophysectomy; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D010868:Pimozide / Q000494:pharmacology; D011893:Rana esculenta / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology; D013737:Testis / Q000187:drug effects*
D000728:Androgens; D010868:Pimozide; D007980:Levodopa; D002064:Buserelin; D004298:Dopamine