Melatonin-insulin interactions in type 2 diabetic rats as well as patients

Introduction: There is a well-documented link between melatonin and insulin. Morphological, molecular and functional investigations have shown that the pineal hormone melatonin (MT) reduces insulin secretion in vitro as well as in control and type 2 diabetic rats. The effects were mediated by specific, high-affinity, pertussis-toxin-sensitive, G-protein-coupled MT1- as well as MT2-membrane receptors, which were detected in the pancreatic tissue of rats and humans, in the islets of rats and in a rat insulinoma b-cell line (INS1). Addressing both the Gi-adenylylcyclase-cAMP and Gi-guanylylcyclase-cGMP pathways, MT…