IMPAIRMENT OF GLYCOPROTEIN SYNTHESIS IN ACUTE ETHANOL INTOXICATION IN RATS

1. 1. Oral inturbation of one intoxicating dose of ethanol to fasted female rats produced fatty livers in 6h. Control rats received an isocaloric dose of glucose solution. 2. 2. Plasma and liver protein synthesis as judged by radioactive leucine incorporation is not impaired by ethanol intoxication. 3. 3. Incorporation of [I-14C]glucosamine into plasma and liver proteins is significantly impaired in ethanol-treated rats. There is also an impairment of radioactivity incorporation into plasma and liver trichloroacetic acid-soluble fractions. 4. 4. The level of hepatic UDP-N-acethylhexosamine and the incorporation of [I-14C]glucosamine into UDP-N-acetylhexosamine fraction is decreased in ethanol intoxaction. Increase of UDP-N-acetylhexosamine level in respose to glucosamine injections is less in ethanol-treated rats, suggesting a bloc in the pathway of synthesis of UDP-N-acetylhexosamine, the known major precursor of glycoproteins. 5. 5. Subcellular fractionation of liver showed a significant impairment of [I-14C]-glucosamine incorporation into smooth microsome and rough membrane proteins in ethanol-treated rats. A small incorporation of radioactivity into the ribosomal fraction is unaffected by ethanol treatment. 6. 6. Synthesis of d 1.006-1.063 plasma lipoproteins as judged by [I-14C]glucosamine incorporation is impaired in ethanol-intoxicated rats. A restriction of glycoprotein synthesis in the microsomal membrane may specifically affect the synthesis of low-density lipoproteins. This subtle alteration of glycoprotein and lipoprotein synthesis might be an important contributing factor for the transient fatty liver in ethanol intoxication. © 1969.