Estimation and Characterization of Prostaglandins in the Human Gastrointestinal Tract

Abstract

Prostaglandin‐like material was extracted from muscle and mucosa of surgically removed human stomach, ileum and colon and assayed against prostaglandin E2 on strips of rat gastric fundus. Superfused human isolated gastric mucosa released prostaglandin‐like material and release was increased by stretching or clamping the tissue. The relative amounts of extracted biological activity were broadly as follows: gastric antral mucosa > colon muscle > gastric body mucosa ≅ ileal mucosa > colon mucosa ≅ gastric muscle ≅ ileal muscle. Prostaglandin E and F were tentatively identified by chromatography and sensitivity to inactivation by alkali. Prostaglandin E apparently contributed most to the biological activity, possibly because the assay tissue is more sensitive to prostaglandin E than to F. Chromatography of gastric body mucosal extracts located material running with prostaglandin E2 and a little with E1. Colonic muscle and mucosal extracts contained material with RF values of prostaglandins E1, E2, E3 and F1α, whereas F2α and F3α‐like substances were found only in the mucosa. The proportions of prostaglandin F varied between specimens. The amount of extracted prostaglandin‐like activity was increased by adding cofactors and arachidonic acid, and lessened by homogenization with acid‐ethanol. The type and amount of activity generated from arachidonic acid by partly purified colonic mucosal prostaglandin synthetase depended on the substrate concentration. The possible relationships of prostaglandins to mucus secretion and other physiological and pathological gut functions are discussed.

Metabolites of Arachidonic Acid Formed by Human Gastrointestinal Tissues and Their Actions on the Muscle Layers

“…It is therefore important to investigate the types of compound formed from eicosatrienoic, eicosatetraenoic (arachidonic) and eicosapentaenoic acids, the C20-unsaturated fatty acid precursors of prostaglandins, and to study their actions on the human gut. Most previous studies have concerned prostaglandin E (PGE) and PGF, compounds (see Bennett, Stamford & Stockley, 1977), but we have now extended the range to include other related metabolites. Preliminary results were described to the Physiological Society .…”

The Contribution of Prostaglandins in the Muscle of Human Isolated Small Intestine to Neurogenic Responses

“…Prostaglandin-like substances have been demonstrated in human stomach (Bennett, Stamford & Unger, 1973), ileum (Stamford, 1976;Bennett, Stamford & Stockley, 1977b) and colon (Bennett, del Tacca, Stamford & Zebro, 1977a;Bennett et al, 1977b), and prostaglandins potently affect strips of human isolated ileal muscle (Bennett, Eley & Scholes, 1968). Studies employing inhibitors of prostaglandin action or synthesis indicate that in isolated intestine, prostaglandins contribute to the regulation of muscle tone and rhythmic activity (Bennett & Posner, 1971;Eckenfels & Vane, 1972;Ferreira, Herman & Vane, 1972;1976;Botting & Salzmann, 1974;Willis, Davison & Ramwell, 1974;Bennett, Eley & Stockley, 1975a;Burleigh, 1977).…”

Evaluation of new therapies for inflammatory bowel disease

“…However, such an approach is much less feasible in Crohn's disease, in which diseased bowel is usually more proximal and less accessible to the endoscopist. Production of mediators can be artefactually modified by the trauma associated with biopsy [74,75]. Furthermore, biopsy is associated with a small risk to patients of bleeding and perforation, particularly in inflamed bowel.…”