Similarly, male and female nNOS−/− mice on a high-fat diet showed little change in body weight and fat mass with EPO treatment (Figure 3; Supplementary Figure S2), consistent with the anti-obesity effect of NOS inhibition (Sansbury and Hill, 2014) that may be specific to the loss of nNOS activity. Here, EPO is linked to obesity due to melanocortin 4 receptor deficiency.