CONTRACTILE AND NONCONTRACTILE PROTEINS AND NUCLEIC-ACIDS IN THE STOMACH, WHOLE JEJUNUM AND SEROMUSCULAR LAYERS OF THE DUODENUM, JEJUNUM, ILEUM AND LARGE-INTESTINE IN RESPONSE TO CHRONIC ETHANOL FEEDING

Rats were fed a nutritionally adequate liquid diet containing 35% of the total calories as ethanol (treated), or identical amounts of the same diet in which ethanol was replaced with isocaloric glucose (controls). At 6 weeks, rats were killed and the stomach (cardiac region), duodenum, jejunum, ileum and the large intestine (combined colon and rectum) were dissected. Seromuscular layers were prepared from the duodenum, jejunum, ileum and the large intestine. After 6 weeks of chronic ethanol feeding the wet weights of the stomach and whole jejunum were reduced by 31%. The wet weights of the duodenum, jejunum and distal ileum seromuscular layers were reduced by 19-25%. The wet weight of the large intestine seromuscular layer was unaltered. The total amounts of contractile and non-contractile protein in the small intestinal seromuscular layers were reduced by 16-52%. In jejunal serosa, the RNA contents were reduced by 29%, but total RNA contents in the serosa of the ileum and duodenum were not significantly altered. Total DNA content was reduced in jejunal and ileal serosal layers by 22 and 33%, respectively, but remained unchanged in duodenal serosa. In the stomach, total contractile and non-contractile protein was reduced by 26-52% and similarly total RNA and DNA were also decreased by 47 and 34%, respectively. Chronic ethanol feeding had no apparent effect on either contractile or non-contractile total protein, total RNA or DNA contents in colonic and rectal serosa. In the combined mucosal and seromuscular layers of the jejunum, much greater effects due to ethanol feeding were observed when compared with the jejunal seromuscular layer alone. The contractile and non-contractile protein contents of the combined mucosal and seromuscular layers of the jejunum were reduced by 57-67%. Total RNA and DNA contents fell by 64 and 55%, respectively. The results re-affirm that the small intestine and cardiac region of the stomach are generally sensitive to chronic ethanol toxicity. The targeting of the seromuscular layer per se, and in particular the contractile proteins contained therein, may have important implications for ethanol-induced motility disturbances.