Impaired mitochondrial protein synthesis in streptozotocin diabetic rat hepatocytes.

Diabetes is associated with decreased protein synthesis; however, there have been very few studies on the effects of insulin or diabetes on mitochondrial protein synthesis. We have recently shown that insulin has a direct stimulatory effect on mitochondrial protein synthesis in isolated rat hepatocytes. In this study we demonstrate that mitochondrial protein synthesis is severely curtailed in hepatocytes isolated from diabetic rats and is unresponsive to in vitro insulin addition. Treatment of diabetic rats with insulin for three days partially restored tracer carbon incorporation in mitochondrial proteins. These results suggest that insulin stimulates hepatic mitochondrial protein synthesis which is significantly impaired in diabetes.