Key Laboratory of Ecological Adaptive Evolution and Conservation on Animals-Plants in Southwest Mountain Ecosystem of Yunnan Province Higher Institutes College, School of Life Sciences, Yunnan Normal University, Kunming, China.
Yunnan College of Business Management, Kunming, China.
J Exp Zool A Ecol Integr Physiol. 2023 Apr;339(3):310-324. doi: 10.1002/jez.2680. Epub 2023 Jan 17.
Melatonin (MEL) is an indole hormone synthesized and secreted by the pineal gland at night, which is involved in the regulation of body mass and thermogenesis in small mammals. To test the effects of exogenous MEL on body mass and thermogenic ability in two different red-backed vole (Eothenomys miletus) populations from two different regions (Kunming [KM] and Dali [DL]) with different annual variation in climatic variables, such as temperature, sunshine and rainfall. we traced the changes of energy balance in E. miletus from KM and DL, which were placed at 25 ± 1°C with photoperiod of 12 L:12 D, intraperitoneal injection of MEL was performed daily for 28 days. The results showed that body mass and food intake were significantly decreased, while resting metabolic rate (RMR) and nonshivering thermogenesis (NST) were significantly increased after MEL injection; Contents of total protein, mitochondrial protein, the activities of cytochrome C oxidase (COX) and α-glycerophosphate oxidase (α-PGO) in liver and brown adipose tissue (BAT) were enhanced; the activity of thyroxin 5'-deiodinase (T 5'-DII) and uncoupling protein 1 (UCP1) in BAT were also increased. Serum leptin, triiodothyronine (T ) levels and T /T ratio were significantly increased, thyroxine (T ) levels was significantly decreased. Moreover, body mass and food intake in E. miletus from KM were higher than those from DL, but RMR and NST were lower than those from DL. Changes of body mass, food intake and thermogenic activity of KM were higher than those of DL when exposed to injection of MEL, indicating that E. miletus in KM were more sensitive to MEL. Furthermore, MEL was involved in the regulation of body mass and thermogenesis in E. miletus between KM and DL.
褪黑素（MEL）是由松果体在夜间合成和分泌的一种吲哚激素，参与调节小型哺乳动物的体重和产热。为了测试外源性 MEL 对来自两个不同地区（昆明[KM]和大理[DL]）的两种不同红背仓鼠（Eothenomys miletus）种群体重和产热能力的影响，这两个地区的气候变量（如温度、阳光和降雨量）年际变化不同。我们跟踪了来自 KM 和 DL 的 E. miletus 的能量平衡变化，它们被放置在 25±1°C，光照周期为 12L：12D，每天进行腹腔注射 MEL，持续 28 天。结果表明，MEL 注射后，体重和食物摄入量显著下降，而静息代谢率（RMR）和非颤抖产热（NST）显著增加；肝和棕色脂肪组织（BAT）中总蛋白、线粒体蛋白、细胞色素 C 氧化酶（COX）和α-甘油磷酸氧化酶（α-PGO）的含量增加；BAT 中的甲状腺素 5'-脱碘酶（T 5'-DII）和解偶联蛋白 1（UCP1）的活性也增加。血清瘦素、三碘甲状腺原氨酸（T ）水平和 T/T 比值显著升高，甲状腺素（T ）水平显著降低。此外，KM 中的 E. miletus 的体重和食物摄入量高于 DL 中的，而 RMR 和 NST 则低于 DL 中的。当暴露于 MEL 注射时，KM 中 E. miletus 的体重、食物摄入和产热活性的变化高于 DL，表明 KM 中的 E. miletus 对 MEL 更为敏感。此外，MEL 参与了 KM 和 DL 之间 E. miletus 体重和产热的调节。
