Melatonin inhibition of pineal enzymes in Coturnix quail.
The activities of the melatonin-forming enzymes hydroxyindole-O-methyl transferase (HIOMT) and N-acetyl transferase (NAT) were determined in pineals of mature female Coturnix quail receiving implants of melatonin (10 mug, 1 mug, 0.1 mug) weekly for 4 weeks. Both HIOMT and NAT were significantly decreased by implants of 10 and 1 mug melatonin compared to vehicle and intact controls. Oviductal weights tended to be higher with increasing quantities of melatonin. These results suggest that melatonin exerts a feedback inhibition upon its synthesizing enzymes which may be of particular importance during the rapid sexual maturation of this species.
D000121:Acetylserotonin O-Methyltransferase / Q000037:antagonists & inhibitors*; D000123:Acetyltransferases / Q000037:antagonists & inhibitors*; D000818:Animals; D003370:Coturnix / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D008550:Melatonin / Q000008:administration & dosage / Q000494:pharmacology*; D008780:Methyltransferases / Q000037:antagonists & inhibitors*; D009929:Organ Size; D010057:Oviducts / Q000187:drug effects; D011784:Quail / Q000378:metabolism*
D008780:Methyltransferases; D000121:Acetylserotonin O-Methyltransferase; D000123:Acetyltransferases; D008550:Melatonin