Muscle damage induced by experimental hypoglycemia

Objective:To study the effects of insulin dosage and duration of hypoglycemia on serum enzyme activity in rabbits,and determine organ damage due to hypoglycemia.Method:Thirty rabbits were randomly divided into five groups according to the duration of hypoglycemia and insulin dose:A 2(hypoglycemia of 30 min duration with 2U/kg insulin),A 10 (hypoglycemia of 30 min duration with 10U/kg insulin),B 2(hypoglycemia of 60 min duration with 2U/kg insulin),B 10 (hypoglycemia of 60 min duration with 10U/kg insulin),and C(no hypoglycemia with 10 U/kg insulin and 50% glucose).Insulin induced hypoglycemia was recovered by intravenous injection of glucose.Alteration in serum enzyme activity and the distribution of creatine kinase(CK) isoenzymes were determined before and after insulin injection.Result:Serum CK activity increased significantly in all the hypoglycemic groups compared to before injection,and tended to remain high for 24h in both groups A 10 and B 10 .Serum activities of alanine aminotransferase(ALT), aspartate aminotransferase(AST) and lactate dehydrogenase(LDH) rose only in group B 10 .In addition,the level of band 4 of the serum CK isoenzymes,which exists predominantly in skeletal muscle and myocardium,increased significantly in group B 10 .Conclusion:The increase in both serum enzyme and CK band 4 isoenzyme activities during hypoglycemia is primarily due to damage in muscle rather than liver,and that the duration of hypoglycemia and insulin dosage may influence the extent of organ damage.