Cell Press, Cell Metabolism, 6(19), p. 1050-1057, 2014
DOI: 10.1016/j.cmet.2014.04.005
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Glucagon-like peptide-1 (GLP-1), an insulinotropic peptide released from the intestine after eating, is essential for normal glucose tolerance (GT). To determine whether this effect is mediated directly by GLP-1 receptors (GLP1R) on islet β-cells, we developed mice with β-cell specific knockdown of Glp1r. β-cell Glp1r knockdown mice had impaired GT after intraperitoneal (IP) glucose, and did not secrete insulin in response to IP or intravenous GLP-1. However, they had normal GT after oral glucose, a response that was impaired by a GLP1R antagonist. β-cell Glp1r knockdown mice had blunted responses to a GLP1R agonist, but intact glucose lowering with a DPP-4 inhibitor. Thus, in mice, β-cell Glp1r are required to respond to hyperglycemia and exogenous GLP-1, but other factors compensate for reduced GLP-1 action on the β-cell during meal ingestion. These results support a role for extra-islet GLP1R in oral glucose tolerance and paracrine regulation of β-cells by islet GLP-1.