RT Journal Article
SR Electronic
T1 Inhibition of Bufalin on Pituitary and Testicular Function in Rats
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 528
OP 532
VO 283
IS 2
A1 Shyi-Wu Wang
A1 Yu-Chung Chiao
A1 Shiow-Chwen Tsai
A1 Chien-Chen Lu
A1 Jiann-Jong Chen
A1 Hsi-Chang Shih
A1 Yen-Hao Chen
A1 Ho Lin
A1 Chii-Min Hwu
A1 Paulus S. Wang
YR 1997
UL http://jpet.aspetjournals.org/content/283/2/528.abstract
AB The effects of bufalin on the secretion of testosterone and luteinizing hormone (LH) and the accumulation of testicular adenosine 3′:5′-cyclic monophosphate (cAMP) were studied. Male rats were injected with bufalin, human chorionic gonadotropin (hCG), gonadotropin releasing hormone (GnRH), hCG plus bufalin or GnRH plus bufalinvia a jugular catheter. Blood samples were collected at several intervals subsequent to the challenge. In the in vitro study, rat testis blocks were incubated with bufalin, hCG or both for 1 h. The anterior pituitary gland was incubated with bufalin, GnRH or both for 30 min. The media were analyzed for testosterone or LH. For studying cAMP accumulation, testicular blocks were incubated for 1 h with the medium containing isobutyl-1-methylxanthine. After incubation, tissues were extracted by ethanol before measuring cAMP concentration. A single intravenous injection of bufalin decreased the basal and hCG-stimulated levels of plasma testosterone. Administration of bufalin in vitroresulted in an inhibition of both basal and hCG-stimulated release of testosterone. Bufalin diminished cAMP accumulation in rat testes. However, the basal levels of plasma and medium LH were not altered by bufalin administration. Likewise, the LH response to GnRH was diminished by bufalin administration, both in vivo andin vitro. These results suggest that the inhibition of testosterone production by bufalin is partly caused by a decrease of testicular cAMP accumulation and LH response to GnRH in rats. The American Society for Pharmacology and Experimental Therapeutics