Effect of insulin on RNA and protein biosynthesis in liver mitochondria from normal and alloxan diabetic rats.

In liver mitochondria from alloxan diabetic rats the biosynthesis of RNA (as measured by 14C-orotic acid incorporation and RNA polymerase activity) and protein (as measured by 14C-leucine incorporation) were decreased. In contrast, insulin (20 U kg-1) injected to intact or diabetic rats increased both these measures. However, no change of mitochondrial DNA biosynthesis (as measured by incorporation of 3H-thymidine) was found. It was concluded that in liver cells insulin plays an important role in regulation of biosynthesis not only of nuclear (cytoplasmic) but also of mitochondrial RNA and proteins.