ORIGINAL ARTICLE

Data source :  Google Scholar QueryDate : 2016-12-24 Cites : 0

Effects of Exogenous Melatonin on Body Mass Regulation and Hormone Concentrations in Eothenomys miletus

By regulating the pineal hormone, photoperiods affect many physiological characteristics in small mammals. Thus, melatonin might take part in the thermoregulation of seasonal variations in small mammals. This study determined the influence of melatonin treatment on thermogenic pattern, we measured body mass, thermogenic activities and hormone concentrations of Eothenomys miletus were given exogenous melatonin (MLT) for 28 days. The results shown that body mass was reduced significantly, whereas resting metabolic rate (RMR) and nonshivering thermogenesis (NST) increased at 28 days in MLT group compared to control group as well as the oxidative capacities of mitochondria in liver and brown adipose tissue (BAT) were enhanced; the contents of total and mitochodrial protein increased markedly. Melatonin treatment significantly increased the State 3, State 4 respiration of liver mitochondria, and the activity of cytochrome C oxidase (COX) in liver; but the α-glerocephasphate oxidase (α-PGO) capacity showed no differences during the acclimation in liver. Furthermore, the State 4 respiration, the activities of COX and α-PGO in BAT increased, respectively. The activity of thyroxin 5’-deiodinase (T₄ 5’-DII) in BAT increased remarkably. The serum content of thyroxine (T₄) decreased, and that of tri-iodothyronine (T₃) increased. Moreover, serum leptin levels showed no significant differences in MLT group compared to control group. Together, these data indicate that melatonin enhances thermogenic capacity in E. miletus. Our results suggested that melatonin is potentially involved in the regulation of body mass, adaptive thermogenic capacity and hormone concentrations in E. miletus.