Lepdb undergoes pancreatic tissue atrophy, including loss of beta cells, which leads to reduced insulin secretion and severe hyperglycaemia combined with obesity and diabetes at a very early age.79Lepob/ob and LepRNull/Null exhibit similar obese phenotypes, and herein we observed comparable reductions in brain weight. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.