Effect of chronic ethanol ingestion on the cyclic AMP system of the upper gastrointestinal tract in the rat.
Chronic ethanol consumption significantly increases gastric adenylate cyclase (AC) activity (p less than 0.05) without influencing low Km 3',5'-cyclic adenosine monophosphate (cAMP) phosphodiesterase (PD) activity in the rat. On the other hand, in the duodenum and upper part of the jejunum, chronic ethanol feeding leads to a significant decrease of adenylate cyclase activity (p less than 0.02) and, again, does not affect low Km cAMP phosphodiesterase activity. In addition, the effect of various hormonal secretagoques on small intestinal adenylate cyclase activity was investigated. Prostaglandin I2 and D2, as well as glucagon, do not stimulate AC at all. However, small intestinal adenylate cyclase exhibits a lower sensitivity to prostaglandin E2 and vasoactive intestinal peptide (VIP), and a lower efficacy to VIP after chronic ethanol consumption when compared to controls. The decrease of both basal and stimulated AC activity following ethanol ingestion in the upper small intestine may be due to membrane alterations and tissue damage caused by ethanol. The ethanol-induced increase in gastric AC may be of relevance with respect to an increased acid secretion observed after alcohol administration.
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000437:Alcoholism / Q000201:enzymology*; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D015232:Dinoprostone; D005753:Gastric Mucosa / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology; D007421:Intestine, Small / Q000187:drug effects; D007700:Kinetics; D008297:Male; D011458:Prostaglandins E / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D011458:Prostaglandins E; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000262:Adenylyl Cyclases; D015232:Dinoprostone