GIP and type 2 diabetes mellitus: In line with these studies, the insulinotropic effectiveness of exogenous GIP (and GLP-1) was improved in individuals with type 2 diabetes after 4 weeks’ treatment with an intensive insulin regimen, leading to a near-normalisation of plasma glucose concentrations [24, 63], also indicating some association of hyperglycaemia with reduced action of incretin hormones, in particular GIP.