Incretin Hormone Antagonism After Bariatric Surgery

Using the glucagon-like peptide-1 (GLP-1) antagonist exendin(9-39) and the glucose-dependent insulinotropic peptide (GIP) antagonist GIP(3-30), the purpose of this study is to clarify the importance of endogenous GLP-1 and GIP for postprandial glucose metabolism after RYGB and SG in subjects with normal glucose tolerance. We hypothesize that GLP-1 is more important after RYGB, and GIP is more important after SG, for postprandial glucose tolerance and beta-cell function. A group of un-operated subjects with normal glucose tolerance will serve as controls.