Calcineurin Inhibitors: Pharmacologic Mechanisms Impacting Both Insulin Resistance and Insulin Secretion Leading to Glucose Dysregulation and Diabetes Mellitus

Calcineurin inhibitors (CNIs), including tacrolimus and cyclosporine, are immune-modulating agents used in autoimmune disorders, glomerulonephritides, and after transplantation. CNIs are implicated as diabetogenic drugs but the mechanism is not clearly elucidated. Calcineurin is a cytosolic-phosphatase critical for T-lymphocyte activation. Calcineurin is widely distributed in different tissues responsible for glucose-regulation including pancreas, liver, skeletal muscle, adipocytes, brain, and gut. We describe the pharmacologic effects of CNIs in different tissues and impact on glucose regulation.