Effects of the β2 -agonist clenbuterol on testicular steroidogenic acute regulatory protein mRNA expression in adult rats.
This study was carried out to investigate the effects of clenbuterol (CLB) on the testicular (steroidogenic acute regulatory, StAR) protein mRNA expression in rats. Thirty adult male rats were administered CLB by gavage daily at the doses of 0.4, 2.0 and 18.5 mg/kg bw for 14 days in the subacute experiment, whereas 20 rats received a single treatment with CLB at the doses of 20 and 40 mg/kg bw in the acute experiment and 20 rats were treated with 0.9% NaCl solution as vehicle groups. Testicular tissues were collected and snap-frozen in liquid nitrogen and stored at -70 °C until use. The levels of StAR mRNA were detected by RT-PCR. The levels of StAR mRNA were markedly increased (P < 0.05) at both dosages of 20 and 40 mg/kg bw but the effects were not dose-dependent and the mRNA levels of StAR were returned to near normal level after 7 days of CLB withdrawal, compared with the control animals. In the subacute experiment, CLB induced a dose-dependent but no statistical significant reduction (P > 0.05) in the expression levels of StAR mRNA, and the mRNA levels were recovered to near normal level in the groups treated with CLB at dosages of 0.4 and 2.0 mg/kg bw/day following a 7-day withdrawal period, compared with the control animals. The mRNA levels of StAR showed a significant decrease in the groups treated with CLB at the dosage of 18.5 mg/kg bw/day (P < 0.05) after a 1- or 7-day withdrawal period with respect to the control animals. These results demonstrated transient stimulative effects of CLB on testicular StAR mRNA levels and inhibitory effects after treatment with CLB for 14 consecutive days.
Institute of Reproductive Immunology, Jinan University, Guangzhou, China.
J-K
JK
Ma
W-J
WJ
Zhu
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002976:Clenbuterol / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D010750:Phosphoproteins / Q000032:analysis / Q000096:biosynthesis* / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D000098682:Steroidogenic Acute Regulatory Protein
D000318:Adrenergic beta-Agonists; D010750:Phosphoproteins; D012333:RNA, Messenger; D000098682:Steroidogenic Acute Regulatory Protein; D002976:Clenbuterol