Particularly RGS4, RGS5, and RGS16 deregulation or decrease in its expression in knockout or knockdown models generates severe metabolic disorders that include increased concentrations of circulating FFA, hepatic steatosis, decreased insulin secretion by pancreatic β-cells, and glucose intolerance, conditions associated with insulin resistance, and T2DM [26,27,28]. This evidence concerns the gene RGS4 and type 2 diabetes mellitus.