Blood Glucose Lowering Effect of Verapamil in Fasted Man

The current study was performed in order to investigate whether verapamil would affect the basal blood glucose concentration in a metabolic state characterized by an increased hepatic gluconeogenesis. For that purpose verapamil (5 mg/h) was infused i.v. during three hours in a group of healthy subjects fasted for 36 h, and for comparison also in healthy subjects fasted overnight. Verapamil was found to lower the basal blood glucose concentration in the 36 h fasted subjects. No effect of verapamil was seen in the overnight-fasted group. Since both the insulin and the glucagon concentrations remained unaffected by verapamil after the 36 h fast, other glucose-regulatory factors must have been responsible for the blood glucose lowering effect of the drug. An effect upon the cytosolic calcium concentration in the hepatocytes causing a decrease in the hepatic gluconeogenesis, is a feasible mechanism by which verapamil might have lowered the blood glucose concentration in the individuals subjected to a prolonged fast.