Effect of Prolonged Alcohol Consumption in Rats on Pancreatic Protein Synthesis ,

Abstract

The objective of this investigation was to determine the effect of prolonged alcohol consumption in rats on the biosynthesis of pancreatic proteins, including trypsin and ribonuclease, employing both in vivo and in vitro techniques. Rats of the Sprague-Dawley strain initially weighing between 250 and 270 g were fed an adequate regular diet and maintained on 20% ethanol as the sole drinking fluid during a 48-week period of observations. Control rats received the same diet with water ad libitum. Pancreatic protein synthesis in vivo and in vitro was studied in these groups at 10-week intervals. The in vivo protein synthesis was evaluated by the incorporation of intravenously injected DL-leucine-1-14C into the pancreatic tissue protein 45 minutes after the injection. For the studies on the in vitro synthesis of protein, slices of the pancreas were incubated for 4 hours with an amino acid mixture containing DL-leucine-1-14C and an ATP-generating system. The protein synthesis was determined by: 1) the incorporation of radioactive leucine into pancreatic protein; 2) by tryptic activity; and 3) ribonuclease activity. Both the in vivo and in vitro experiments demonstrated that there is a decrease in protein synthesis including that of trypsin and ribonuclease by the pancreas of animals maintained on 20% ethanol. Food intake determinations indicated that the foregoing results were due to an effect of ethanol per se on pancreatic tissue, rather than to any major alteration of caloric or protein intake.