THE EFFECT OF INSULIN AND GLUCOSE ON THE MYOCARDIAL AND SKELETAL MUSCLE UPTAKE OF TRITIATED DIGOXIN IN ACUTELY HYPOKALEMIC AND NORMOKALEMIC DOGS

¹ The Cardiology Section, Department of Internal Medicine, University of Arizona, Arizona Medical Center, Tucson, Arizona

An infusion of glucose and insulin, whether or not accompained by hypokalemia, was associated with an increase in the skeletal muscle concentration of ³H-digoxin in the dog. Hypokalemia induced in dogs by glucose and insulin did not cause an increase in total digoxin content of the heart, nor did it result in an increase in the biliary excretion of the drug. The concentration of digoxin in whole blood was decreased when the drug was injected during glucose and insulin infusion, but not during infusion of glucose, insulin and potassium. If digoxin is injected during glucose and insulin infusion, the blood concentration may not reflect the myocardial concentration of this drug, since the myocardial/blood ratio may be increased under these circumstances. These data may be interpreted as indicative of an enhanced uptake of digoxin by the heart under hypokalemic conditions since, with presumably lower plasma levels, the heart was still able to maintain its myocardial content of digoxin.