title: Melatonin increases muscle and liver glycogen content in nonexercised and exercised rats.
abstract: The effects of melatonin on several parameters of carbohydrate and lipid metabolism were investigated in exercised and nonexercised rats. Animals were run to exhaustion on a rodent treadmill at 24 m/min and a 12% slope. Exercise resulted in a significant hypoglycemia and increased plasma levels of lactate and beta-hydroxybutyrate, together with a significant reduction of glycogen in muscle and liver. Muscle and liver glycogen content was elevated and plasma free fatty acid decreased in nonexercised animals receiving melatonin (0.5 or 2.0 mg/kg i.p). Melatonin at 2.0 mg/kg reduced plasma lactate and increased lactate concentration in liver. When compared to untreated exercised animals glycemia and muscle and liver glycogen content were significantly higher in melatonin-treated exercised animals, while plasma and liver lactate and plasma beta-hydroxybutyrate were significantly reduced. Our data indicate that melatonin preserves glycogen stores in exercised rats through changes in carbohydrate and lipid utilization.
authors.affiliation: Department of Physiology, University of León, Spain.
authors.forename: R C
authors.initials: RC
authors.lastname: Mazepa
authors.forename: M J
authors.initials: MJ
authors.lastname: Cuevas
authors.forename: P S
authors.initials: PS
authors.lastname: Collado
authors.forename: J
authors.initials: J
authors.lastname: González-Gallego
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D050356:Lipid Metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008112:Liver Glycogen / Q000096:biosynthesis*; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D005082:Physical Exertion; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000975:Antioxidants; D008112:Liver Glycogen; D008550:Melatonin