DEPRESSION OF RESPIRATORY ACTIVITIES IN LIVER MITOCHONDRIA OF DIABETIC RATS AND RESTORATIVE ACTION OF INSULIN

Liver mitochondria from normal, alloxan-treated and pancreatectomized rats were prepared and the respiratory activities were measured polarographically. The respiratory pattern of mitochondria from diabetic animals showed more uncoupled respiration than mitochondria from normal animals. The P: O ratios and the respiratory control ratios of mitochondria from diabetic rats were lower than those of mitochondria from normal rats, but were rapidly restored to normal levels by the administration of insulin. The content of nonesterified fatty acids in the mitochondrial fraction increased in the livers of diabetic rats, and the administration of insulin decreased this elevated fatty acid level to normal.A possible explanation for these results is presented, with particular concern in the relation between respiratory activities in mitochondria and the effects of insulin on lipid metabolism. © 1969 BY THE JOURNAL OF BIOCHEMISTRY.