title: Adaptations of the aging animal to exercise: role of daily supplementation with melatonin.
abstract: The pineal gland, through melatonin, seems to be of fundamental importance in determining the metabolic adaptations of adipose and muscle tissues to physical training. Evidence shows that pinealectomized animals fail to develop adaptive metabolic changes in response to aerobic exercise and therefore do not exhibit the same performance as control-trained animals. The known prominent reduction in melatonin synthesis in aging animals led us to investigate the metabolic adaptations to physical training in aged animals with and without daily melatonin replacement. Male Wistar rats were assigned to four groups: sedentary control (SC), trained control (TC), sedentary treated with melatonin (SM), and trained treated with melatonin (TM). Melatonin supplementation lasted 16 wk, and the animals were subjected to exercise during the last 8 wk of the experiment. After euthanasia, samples of liver, muscle, and adipose tissues were collected for analysis. Trained animals treated with melatonin presented better results in the following parameters: glucose tolerance, physical capacity, citrate synthase activity, hepatic and muscular glycogen content, body weight, protein expression of phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinase (MAPK), and protein kinase activated by adenosine monophosphate (AMPK) in the liver, as well as the protein expression of the glucose transporter type 4 (GLUT4) and AMPK in the muscle. In conclusion, these results demonstrate that melatonin supplementation in aging animals is of great importance for the required metabolic adaptations induced by aerobic exercise. Adequate levels of circulating melatonin are, therefore, necessary to improve energetic metabolism efficiency, reducing body weight and increasing insulin sensitivity.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences-I, University of São Paulo (USP), São Paulo, SP, Brazil.
authors.forename: Caroline
authors.initials: C
authors.lastname: Mendes
authors.forename: Ana Maria de Souza
authors.initials: AM
authors.lastname: Lopes
authors.forename: Fernanda Gaspar
authors.initials: FG
authors.lastname: do Amaral
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Peliciari-Garcia
authors.forename: Ariane de Oliveira
authors.initials: Ade O
authors.lastname: Turati
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Hirabara
authors.forename: Julieta H
authors.initials: JH
authors.lastname: Scialfa Falcão
authors.forename: José
authors.initials: J
authors.lastname: Cipolla-Neto
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000273:Adipose Tissue / Q000378:metabolism; D000375:Aging / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D019587:Dietary Supplements; D008099:Liver / Q000378:metabolism; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000378:metabolism; D010805:Physical Conditioning, Animal; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000975:Antioxidants; D008550:Melatonin
keywords: aging; exercise; melatonin; metabolic adaptations; pineal gland