GLP1R and obesity due to melanocortin 4 receptor deficiency: Besides its efficacies for controlling hyperglycemia in T2D, GPR40 agonists have also been shown to be potentially applicable for other indications, including obesity and NASH, inflammatory bowel diseases, neurodegenerative diseases, etc. GPR40 plays an important role in regulating GLP-1 and other intestine incretin secretion.