MODERATE DIABETES ALTERS MYOSIN ISOENZYME DISTRIBUTION IN CARDIAC BUTNOT SKELETAL-MUSCLE OF MALE-RATS

Diabetes is known to alter the myosin phenotype of striated muscle, bu t the impact of the same diabetic state on different types of striated muscles remains unknown. Therefore, this study determined the myosin isoenzyme profile in the left ventricle, soleus, plantaris, and extens or digitorium longus (EDL) of young male rats made moderately diabetic with streptozotocin, (45 mg/kg, ip). Eight weeks after the single str eptozotocin injection, tissues were collected and subsequently electro phoretically analyzed for native myosin isoenzyme distribution. Skelet al muscles were additionally analyzed for myosin heavy chain distribut ion. Neither the native myosin isoform nor the myosin heavy chain (MHC ) distribution profiles of the skeletal muscles were altered by the di abetic state. In contrast, the high ATPase cardiac isoform, V1, was si gnificantly replaced by the low ATPase isoform, V3 (p < 0.05). These r esults demonstrate that striated muscle responds to a moderate diabeti c state in a limited and muscle specific fashion. Significantly, the c hange in the cardiac myosin isoform profile is comparable to that whic h occurs in a more severe diabetic state.