GCG and obesity due to melanocortin 4 receptor deficiency: Obesity is well-known to increaseinsulin secretion, and in rodent models causes beta cell hyperplasia.21 In type 2 diabetes (T2DM) and diabetic mousemodels, there have been reports of beta cell dedifferentiation,22−24 increased alpha cell numbers, and islet GLP-1 production.1,2