1. Efficiency of preventive and reversive insulin therapy was compared on rat myocardium following streptozotocin treatment to study the reversibility of diabetic catecholamine resistance. 2. When insulin substitution was initiated immediately after streptozotocin treatment, insulin successfully prevented the development of diabetic catecholamine resistance of the myocardium. 3. When insulin substitution was initiated following the development of isoproterenol resistance, insulin failed to restore physiological catecholamine sensitivity. 4. These results indicate that once diabetic alterations have already developed, recovery of biological functions to normal by exogenous insulin substitution might be ineffective.
Animals Cardiotonic Agents