The effect of the administration of carbon tetrachloride on the formation of plasma lipoproteins in the rat

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Abstract
The administration of a mixture of CCl4 and olive oil to female rats led to the following changes at 24 hours in the liver and. plasma lipids: a rise in the amount of esterified fatty acids in the liver from 196 to 569 mg; a rise in the amount of cholesterol in the liver from 21 to 30 mg; (c) a fall in the concentration of esterified fatty acids in the plasma from 1:37 to 0.58 mg/ml; a fall in the concentration of cholesterol in the plasma from 0.60 to 0.32 mg/ml; a fall in the concentration of phosphatides in the plasma from 1.03 to 0.54 mg/ml. At 2 hours after the same dose of CCl4 the incorporation of DL-[1-C14] leucine, injected in vivo, into the low-density lipoproteins, high-density lipoproteins and residue proteins of the plasma was respectively 9.3, 12.7 and 16.7% of the incorporation into the corresponding fractions in control animals given olive oil alone. Incorporation into the liver protein was reduced to 21.6% of the level in control animals. Liver slices from rats dosed with CCl4, incubated in vitro in a serum medium containing DL-[-C14] leucine, showed similar reductions of incorporation into plasma proteins. The reduction of incorporation into the liver proteins was less marked. A significant reduction of the incorporation of [P32] orthophosphate into the phosphatides of liver and of plasma was found in vivo 3 hours after the administration of CCl4. The incorporation of [P32] orthophosphate into plasma phosphatides in vitro was not significantly affected 2 hours after the administration of CCl4. At 0.5, 1 and 2 hours after the injection of sodium [1-C14] acetate the specific activities of the cholesterol of liver and of plasma were lower in animals given carbon tetrachloride 2 hours previously than in control animals. These results suggest that inhibition of the formation of plasma lipoprotein may be a cause of the fatty livers and of the lowered concentrations of plasma lipid in CCl4-treated animals.