INS and obesity due to melanocortin 4 receptor deficiency: Excessive glucocorticoid action has been implicated in the development of several phenotypes associated with metabolic syndrome, such as obesity and type 2 diabetes.6–8 Studies show that glucocorticoid receptor (GR) activation stimulates hepatic glucose production, antagonises insulin secretion from pancreatic β-cells and insulin-mediated glucose uptake in peripheral tissues.9