Melatonin modulates swine luteal and adipose stromal cell functions.

Based on our previous study in follicles, the first aim of this work was to evaluate the effect of melatonin in the swine corpus luteum (CL). Luteal cells were exposed to 10 and 20pg mL-1 melatonin. We evaluated the effect on proliferation (bromo-deoxy-uridine uptake), steroidogenesis (progesterone) and redox status by means of Griess test (nitric oxide production), WST-1 test (superoxide anion generation) and FRAP test (non-enzymatic antioxidant power). The results showed a significant increase in antioxidant power, as well as a reduction in the other parameters analysed. These data and the expression of MT2 observed in luteal cells allow us to hypothesise a physiological role of melatonin in the regulation of CL functionality. The reproductive function is dependent on energy reserves stored in adipose tissue. Therefore, we sought to verify the effect of melatonin on adipose stromal cells (ASCs). MT2 receptor expression was detected in ASCs and the presence of gene markers (PPARγ and leptin) before and after adipogenic differentiation was verified. The differentiation was significantly inhibited by melatonin, as well as cell viability. In conclusion, present results suggest that melatonin exerts a potential inhibitory action on luteal function and adipogenesis, possibly mediated by MT2.