Secretion of glucagon-like peptide-1 in patients with type 2 diabetes mellitus: systematic review and meta-analyses of clinical studies.

We carried out a systematic review of clinical studies investigating glucagon-like peptide-1 (GLP-1) secretion in patients with type 2 diabetes and non-diabetic controls and performed meta-analyses of plasma total GLP-1 concentrations during an OGTT and/or meal test.