Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
J Pineal Res. 2010 Nov;49(4):342-8. doi: 10.1111/j.1600-079X.2010.00798.x.
Melatonin effect on body weight progression, mean levels and 24-hr pattern of circulating adiponectin, leptin, insulin, glucose, triglycerides and cholesterol were examined in rats fed a normal or a high-fat diet. In experiment 1, rats fed a normal diet were divided into two groups: receiving melatonin (25 μg/mL drinking water) or vehicle for 9 wk. In experiment 2, animals were divided into three groups: two fed with a high-fat diet (35% fat) and melatonin (25 μg/mL) or vehicle in drinking water for 11 wk, while a third group was given a normal diet (4% fat). At the end of experiments, groups of eight rats were killed at six different time intervals throughout a 24-hr period. Melatonin administration for 9 wk decreased body weight gain from the 3rd wk on without affecting food intake. A significant reduction in circulating insulin, glucose and triglyceride mean levels and disrupted daily patterns of plasma adiponectin, leptin and insulin were observed after melatonin. In high fat-fed rats, melatonin attenuated body weight increase, hyperglycemia and hyperinsulinemia, as well as the increase in mean plasma adiponectin, leptin, triglycerides and cholesterol levels. The high-fat diet disrupted normal 24-hr patterns of circulating adiponectin, insulin and cholesterol, the effects on insulin and cholesterol being counteracted by melatonin. Nocturnal plasma melatonin concentration in control and obese rats receiving melatonin for 11 wk attained values 21-24-fold greater than controls. The results indicate that melatonin counteracts some of the disrupting effects of diet-induced obesity in rats.
褪黑素对体重进展、循环脂联素、瘦素、胰岛素、葡萄糖、甘油三酯和胆固醇的平均水平及 24 小时模式的影响在正常或高脂肪饮食喂养的大鼠中进行了研究。在实验 1 中，正常饮食喂养的大鼠分为两组：接受褪黑素（25μg/mL 饮用水）或载体 9 周。在实验 2 中，动物分为三组：两组给予高脂肪饮食（35%脂肪）和褪黑素（25μg/mL）或饮用水中的载体 11 周，而第三组给予正常饮食（4%脂肪）。在实验结束时，8 只大鼠的 6 个不同时间间隔在 24 小时内被杀死。褪黑素给药 9 周后，从第 3 周开始体重增加减少，但不影响食物摄入。褪黑素后观察到循环胰岛素、葡萄糖和甘油三酯平均水平显著降低，以及血浆脂联素、瘦素和胰岛素的日常模式中断。在高脂肪喂养的大鼠中，褪黑素减轻了体重增加、高血糖和高胰岛素血症，以及平均血浆脂联素、瘦素、甘油三酯和胆固醇水平的增加。高脂肪饮食破坏了循环脂联素、胰岛素和胆固醇的正常 24 小时模式，而褪黑素对胰岛素和胆固醇的影响则相反。在接受 11 周褪黑素治疗的对照和肥胖大鼠中，夜间血浆褪黑素浓度达到对照的 21-24 倍。结果表明，褪黑素拮抗了饮食诱导肥胖对大鼠的一些破坏作用。
