GLP1R and type 2 diabetes mellitus: People with type 2 diabetes and MetS frequently have reduced GLP-1 production in response to meals; this condition is referred to as “incretin deficiency.” Additionally, the short half-life (less than two minutes) of natural GLP-1 limits its bioactivity since the ubiquitous enzyme dipeptidyl peptidase-4 (DPP-4) quickly breaks it down.