Preserved incretin activity of glucagon-like peptide 1 [7-36 amide] but not of synthetic human gastric inhibitory polypeptide in patients with type-2 diabetes mellitus. - Nauck,M.A.; Heimesaat,M.M.; Ørskov,C.; Holst,J.J.; Ebert,R.; Creutzfeldt,W. (J Clin Invest, 1993)