NPY and obesity due to melanocortin 4 receptor deficiency: To this end, we aimed to test the anti-obesity effects of chronic treatment with a specific Y2-receptor antagonist with a potential clinical application to be obesity and metabolic disorders due to NPY excess induced by chronic stress or genetic factors (gain-of-function polymorphisms) (Karvonen et al., 1998; Ding et al., 2005; Masoudi-Kazemabad et al., 2013).