EPO and obesity due to melanocortin 4 receptor deficiency: In this regard, several studies suggest that EPO plays a role in the regulation of mitochondrial function: it has been shown to stimulate muscle fat oxidation and to prevent diet-induced obesity in mice [40], to promote muscle mitochondrial biogenesis in rats [41] and to enhance mitochondrial function (oxidative phosphorylation and electron transport capacity) in humans [42].