ADCY3 and obesity due to melanocortin 4 receptor deficiency: GK rats, a hereditary nonobese animal model of T2D, exhibit elevated AC3 expression levels in the pancreatic islets and significantly reduced BWs compared with Wistar rats.23 Mice carrying the AC3Jll mutant allele exhibit increased AC3 activity in response to forskolin and are protected from HFD-induced obesity.24 In the present study, liraglutide upregulated the hepatic and serum AC3 levels.