[Bioenergetics of liver mitochondria in rats in experimental insulin-dependent diabetes]. / Bioenergetika mitochondrií pecene potkana pri experimentálnom inzulíndependentnom diabete.

Oxidative stress in the course of diabetes mellitus can cause disturbance of lipid membranes of cellular organelles. The study is aimed at the determination of oxidative phosphorylation in mitochondria in rats with experimentally induced acute and chronic insulin-dependent diabetes mellitus (IDDM). IDDM was induced by single dose of streptozotocin (45 mg per kg-1). Insulin Interdep (6 U per kg-1) was administered once a day subcutaneously. The authors investigated glycaemia, cholesterol and triacylglycerol concentrations in the blood and liver. Isolation of mitochondria was succeeded by measurement of oxidative phosphorylation indicators after 8 days (acute IDDM) or after 8 weeks (chronic IDDM) from streptozotocin administration. The authors found out that both acute and chronic IDDM were concommited by hyperglycaemia. The group with acute IDDM yielded an increase in cholesterol and triacyglycerols concentrations in the blood, as well as that of cholesterol in the liver. The group with chronic IDDM yields an increase in cholesterol in the blood. Trialcylglycerols in the liver increased in none of the investigated groups. Liver steatosis did not occur. Indicators of oxidative phosphorylation in the liver mitochondria of rats with acute and with chronic IDDM decreased in contrast to healthy controls from NAD substrates glutamate and pyruvate and also form FAD substrate of succinate. Significant decrease in consumption of oxygen in the 3 state occurred, while in acute IDDM the decrease was more significant than in chronic IDDM. Phosphorylation rate significantly decreased in contrast to controls, but there was no difference between IDDM groups. The investigation results imply that in both acute and chronic IDDM there are decreased effectivity of energetic metabolism in liver mitochondria. (Tab. 5, Ref. 29.).

[Oxidative phosphorylation in liver mitochondria after injury with carbon tetrachloride and during regeneration]. / Oxidacná fosforylácia v mitochondriách pecene po poskodení chloridom uhlicitým a pocas regenerácie.

The study investigates the effect of a singular dose of CCl4 (2.5 ml/kg) on the concentration of triacylglycerols in the liver and oxidative phosphorylation in hepatic mitochondria after 24, 72 hours, 2 and 4 weeks since CCl4 application. It was discovered that 24 and 72 hours after CCl4 application the concentration of triacylglycerols increased significantly and steatosis of the liver supervened. After 2 and 4 weeks the triacylglycerol concentration values reached the level of those of control. The hepatic steatosis disappeared. The indices of oxidative phosphorylation index of respiration control, oxygen consumption during stimulated respiration (state 3), oxygen consumption during basal respiration (state 4), and phosphorylation velocity decreased significantly after 24 and 72 hours after CCl4 application in all observed substrates--glutamate, pyruvate and jantarane. After 2 to 4 weeks the observed indices reached the level of values characteristic for healthy controls. The results have indicated that after the CCl4 toxic impairment the energy metabolism in hepatic mitochondria has been significantly impaired. This impairment, in spite of its severeness, was irreversible and hepatocytes were able to compensate it (Tab. 4, Ref. 33).