Following treatment with PRL, HFD-fed mice displayed a significant improvement in insulin-induced glucose-lowering effect during an insulin tolerance test and a significant reduction in adipocyte hypertrophy in visceral adipose tissue as compared with HFD-fed animals not receiving treatment with PRL and control diet-fed animals [49], therefore leading to the conclusion that in obesity conditions PRL plays a crucial role in the promotion of a healthier form of adipose tissue growth with enhanced metabolic performance [49]. Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.