FIGURE 3.
Metabolic and immune effects of melatonin in rodent models. High‐fat diet (HFD) mice exposed to constant light for 24 h showed dysregulated circadian rhythms accompanied by increased body weight. On the hepatic level, mice displayed upregulated levels of Fas and Srebp1 genes, which are associated with hepatomegaly and steatosis. These mice were also hyperglycemic and insulin resistant, and treatment with melatonin improved their metabolic profile by decreasing body weight and downregulating Fas and Srebp1 gene expression in the liver. Thus, hepatic steatosis decreased, and systemic insulin sensitivity and glycemia were improved. 59 Pinealectomized rats exposed to constant light showed decreased levels of thymosin α1 and thymulin, which are important factors secreted by the thymus involved in the maturation of immune cells (B cells, T cells, and natural killer cells). Interestingly, melatonin supplementation in this rat model promoted the secretion of thymosin α1 and thymulin, thus improving cell‐mediated immunity. 83 Illustrations created with BioRender.com