10. PHYSIOLOGICAL ROLE OF INCRETINS
Physiology of GLP-1 secretion and action on GLP-1 receptors in different organs and tissues. GLP-1 is
produced postprandially by intestinal L-cells. Through activation of insulin receptors on beta-cells GLP-1
(like GIP) stimulates insulin biosynthesis and secretion and inhibits glucagon secretion in the pancreas,
which in turn reduces hepatic gluconeogenesis. GLP-1 release also exerts protective effects on heart and
brain. Insulin sensitivity in the periphery is increased by improved insulin signaling and reduced
gluconeogenesis. Figure modified with permission from Cell Metabolism [3]