We recently demonstrated that blockade of Glucagon-Like Peptide-1's (GLP-1) receptor (GLP1R) results in changes in islet function without changes in circulating GLP-1. These effects are more pronounced in people with early type 2 diabetes (T2DM) in keeping with increased expression of PC-1/3 and GLP-1 that is observed in diabetic islets. However, its regulation is at present unknown. At present it is unknown if these abnormalities develop in prediabetes and whether they contribute to the phenotypes observed. In this experiment we will use blockade of GLP1R to probe the contribution of endogenous GLP-1 secretion to the regulation of fasting glucose and islet function in prediabetes.