In line with their proposed mechanisms of action in T2DM, β3-AR agonists did not improve hyperglycemia in rodent models of type 1 diabetes (T1DM), e.g., as induced by streptozotocin or alloxan [15]; therefore, data related to T1DM will not be covered here systematically. This evidence concerns the gene ADRB3 and type 2 diabetes mellitus.