[Changes in lipid and carbohydrate metabolism in rat tissues under combined effect of hypercapnia, hypoxia and...

The cooling of rats under conditions of hypercapnia and hypoxia during the first 15 minutes increases the contents of free fatty acids, acetoacetate and beta-oxybutyrate in the tissues of the brain, myocardium, liver, skeletal muscles and blood and decreases them by the end of the effect (120 min later) down to the initial values, in the liver and skeletal muscles tissues the content of the mentioned intermediates falls lower the initial values. In the carbohydrate metabolism the amount of phosphoenolpyruvate 15 and 120 min after the action beginning and the amount of malate in the myocardium and brain at the end of the experiment increase to a different extent; the content of lactate rises only in the brain 30 and 120 min after the beginning of cooling. In the rat venous blood the value of pCO2 increases up to 71.8+/-6.0 mm Hg, the total content of CO2 rises, the values of the standard bicarbonates decrease and the pH value drops sharply down to 6.98+/-0.03. It is suggested that one of the main reasons of such changes in metabolism is development of hypercapnia state and acidosis and the resulted increase in intensity of the carboxylation processes in the tissues.