Diurnal variation in the effect of melatonin on plasma and muscle free fatty acid levels in the pigeon.
Pigeons maintained on standard diet and held under 12 h daily photo-period in a controlled environmental room, were given intravenous injections of melatonin. A low dose (1.25 mg/kg body weight) of melatonin when given in the middle of the scotophase, produced a significant increase in plasma FFA when estimated at 20 min and 90 min post-injection, whereas no significant change was seen with injections given in the middle of the photophase. No significant change in muscle FFA level was obtained either during the photophase or the scotophase when estimated at 90 min postinjection. With a higher dose (5 mg/kg body weight) of melatonin given in the scotophase, on the other hand, a significant increase in both plasma as well as muscle FFA levels was obtained at 90 min post-injection but there was no effect on plasma FFA at 20 min or 90 min post-injection in the photophase and at 20 min in the scotophase. It is concluded that melatonin has a lipid mobilizing action in the pigeon when administered during the scotophase.
D000818:Animals; D002940:Circadian Rhythm; D010856:Columbidae / Q000097:blood / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000097:blood / Q000378:metabolism*; D008550:Melatonin / Q000494:pharmacology*; D009132:Muscles / Q000378:metabolism*
D005230:Fatty Acids, Nonesterified; D008550:Melatonin