STAMBP and Insulin resistance: For instance, mice lacking the 5-HT2C receptor develop insulin resistance and type 2 diabetes and later overeat and become obese, whereas a drug that acts on 5-HT2C receptors improved glucose tolerance without leading to reductions in food intake or body weight by stimulating melanocyte-stimulating hormone (α-MSH) in the brain's arcuate nucleus, a portion of the hypothalamus that has a role in appetite control.