Decrease of phosphorylating oxidation and increase of heat producing NADH oxidation in rat liver mitochondria during life-span prolongation of rats by calorie-restricted diet.

The influence of calorie-restricted diet, initiated at weaning, on some of the oxidative processes in liver homogenates and isolated mitochondria of 2-, 3-, 4-, 24-, 35- and 45-month-old male Wistar rats was studied in comparison with control ad libitum-fed 1-2 day-old rats and 0.5-, 1-, 2-, 3-, 4- and 24-month-old rats. It was shown that a calorie-restricted diet (at 37% of the ad libitum calorific level) did not change the rate of succinate oxidation coupled with oxidative phosphorylation in homogenates, but resulted in a decrease of succinate, glutamate plus malate and beta-hydroxybutyrate oxidation and cytochrome c-oxidase activity in isolated mitochondria without any uncoupling of oxidative phosphorylation or change in cytochrome content in the mitochondria. On the other hand, a significant increase in mitochondrial rotenone-insensitive NADH oxidation and a higher liver mass/body mass ratio in rats under the calorie-restricted diet was established. It may be considered that the activation of a heat-producing mechanism is a very important physiological function in such a condition.