The function of prostaglandins in transmucosal water movement and blood flow in the rat jejunum

Abstract

Jejunal loops of anaesthetized rats were perfused with isotonic buffer containing PGE₁, PGF_2α or indomethacin. Intestinal blood flow, absorption and secretion of tritiated water were measured. PGE₁ at the low concentration of 0.1 μg ml⁻¹ did not influence intestinal blood flow but increased secretion and decreased absorption of tritiated water. In higher concentrations (0.5 and 6.5 μg ml⁻¹), blood flow, secretion and absorption were enhanced. PGF_2α, even in the high concentration of 50 μg ml⁻¹, did not influence intestinal blood flow but enhanced secretion and decreased absorption of tritiated waterl. Indomethacin (1 μg ml⁻¹) decreased intestinal blood flow and secretion but enhanced absorption of tritiated water. The effects of indomethacin on blood flow can be prevented and those on secretion can be even reversed by an additional infusion of PGE₁ (0.5 μg ml⁻¹) PGs appear to play a physiological role in the regulation of intestinal blood flow and transmucosal water movement, since inhibition of endogenous PG synthesis by indomethacin results in effects opposite to those of intraluminally applied PGE₁. The results obtained with the low concentration of PGE₁ (0.1 μg ml⁻¹) and with PGF_2α (50 μg ml⁻¹) strongly indicate that intestinal water movement can be changed independently of intestinal blood flow.