Protein kinase C activity is altered in diabetic rat hearts

An elevation in diacylglycerol content in the myocardium from diabetic rats has been reported. Since diacylglycerol is known to be an important second messenger in activating protein kinase C, we carried out a study to investigate the status of protein kinase C activity in the hearts of Wistar diabetic rats. Our results showed that protein kinase C activity was significantly increased in the membrane fraction of diabetic hearts compared with controls, and the increased activity was accompanied by a decrease in cytosolic protein kinase C activity in these diabetic hearts. The increase in the membrane-bound protein kinase C activity thus appears to be due to translocation of the enzyme from the cytosolic to the membrane fraction. These results indicate that the development of diabetic cardiomyopathy is accompanied with a high membrane-bound protein kinase C level.