The effect of repeated amphetamine administration on the proopiomelanocortin mRNA level in the rat pituitary: an in situ hybridization study.
The effect of single and repeated administration of amphetamine (5 mg/kg i.p., twice daily, 14 days) on the proopiomelanocortin (POMC) mRNA level was investigated in the rat pituitary. In situ hybridization histochemistry, using a 35S-d-ATP-labelled deoxyoligonucleotide probe and densitometric analysis of autoradiograms, showed that repeated administration of amphetamine moderately increased the POMC mRNA level (by approximately 16%) in the anterior and the intermediate lobes of the pituitary at 72, but not 2, hr after the last injection. Adrenalectomy (48 h after the last drug injection) increased the POMC mRNA level only in the anterior lobe of repeated saline- and amphetamine-treated rats by 59 and 67%, respectively. No significant changes in POMC mRNA level in either lobe were found following single administration of amphetamine. These results suggest that repeated amphetamine administration leads to a delayed and moderate increase in POMC biosynthesis in the rat pituitary. On the other hand, the responsiveness of the POMC pituitary system to adrenalectomy was not significantly altered in rats treated repeatedly with amphetamine.
Jaworska
L
L
Department of Endocrinology, Polish Academy of Sciences, Kraków.
Budziszewska
B
B
Lasoń
W
W
D000315:Adrenalectomy; D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D017403:In Situ Hybridization; D007274:Injections, Intraperitoneal; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects* / Q000473:pathology; D011333:Pro-Opiomelanocortin / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D017208:Rats, Wistar
D012333:RNA, Messenger; D011333:Pro-Opiomelanocortin; D000661:Amphetamine