Effect of prostacyclin (PGI2) on water and solute transport in the human jejunum.

Abstract

SUMMARY Prostacyclin is an arachidonic acid metabolite, synthesised throughout the gastrointestinal tract, which has different effects on water and electrolyte transport across a variety of mammalian gastrointestinal epithelia. Using a perfusion technique in the human jejunum of 11 healthy subjects in vivo, the effect of intravenous prostacyclin, 4 ng/kg/min, on jejunal water and solute transport from a glucose electrolyte solution was investigated. In the prostacyclin group (n=5), prostacyclin was infused intravenously from 70-150 minutes, and buffer administered iv from 0-70 and 150-210 minutes. In the buffer group (n=6), iv buffer was administered from 0-210 minutes. In the prostacyclin group, net jejunal absorption of water was inhibited from 90-120 min (p<0 05), 150-180 min (p<0.01) and 180-210 min (p<0O01), of sodium was inhibited from 90-120 min (p<0 05), 120-150 min (p<0-05), 150-180 min (p<0 01) and 180-210 min (p<O.Ol), and of chloride was inhibited from 90-120 min (p<005), 120-150 min (p<0.005), 150-180 min (p<001) and 180-210 min (p<001). Prostacyclin had no effect on net movement of glucose, potassium or bicarbonate. These results are consistent with a role for prostacyclin in the endogenous humoral regulation of water and electrolyte transport in the human jejunum.Prostacyclin (PGI2), in common with other prostaglandins, is an arachidonic acid metabolite, which is synthesised throughout the gastrointestinal tract. 1 In tissues, arachidonic acid is released from membrane-bound phospholipids in response to a variety of physical and neurohumoral stimuli2 and is then oxidised by the enzyme cyclooxygenase to PGI2, PGE2, PGF2,,, and other metabolites.Recent evidence has suggested that prostaglandins act as endogenous regulators of intestinal water and electrolyte transport. 4The role of PGI2 in this respect is unclear, because previous reports of its effect on water and ion transport across mammalian gastrointestinal epithelia have varied depending on the species studied and the experimental techniques used. In one study in the rat small intestine, PGI2 reduced luminal fluid accumulation ('enteropooling') and also inhibited enteropooling caused by choleragen and 16,16-dimethyl PGE2.5 Prostacyclin decreased short circuit current across human jejunal mucosa in vitro,6 which suggested that it might also Address for correspondence: Dr K J Moriarty, Department of Medicine, Hope Hospital, Salford M6 8HD. Received for publication 3 June 1985 possess antisecretory properties in man. PGI2 elicits a secretagogue response, however, both in the rat jejunum and colon7 and in the guinea pig gall bladder.8In view of these findings, the present study was done to investigate the effect of PGI2 on water and solute transport in the human jejunum in vivo. Methods SUBJECTSEleven healthy subjects (five men, six women), aged 20-40 years, gave written informed consent for the study, which was approved by the ethical committee of St Bartholomew's Hospital, London.

PGI2 Inhibits Intestinal Epithelial Permeability and Apoptosis to Alleviate Colitis

“… 65 Its well-described impact on the IEB itself includes reduction of acid secretion, 66 , 67 induction of chloride secretion, 68 , 69 and inhibition of water and solute absorption. 70 , 71 Concerning PGI 2 regulation of IEC proliferation or apoptosis, studies are contradictory. PGI 2 promotes HT29 cell proliferation in vitro 72 but does not stimulate growth of gastroduodenal mucosa in vivo.…”