CYSTEAMINE AND PROSTAGLANDIN-F 2-BETA STIMULATE RAT GASTRIC MUCIN RELEASE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 84  (2) , 306-313
Abstract
Gastric mucin glycoproteins form an adherent gel over the surface epithelium that is thought to protect the stomach against chemical and physical damage. The release of mucin glycoproteins from rat stomach after treatment with cysteamine and prostaglandin F2.beta., 2 structurally unrelated drugs that have been shown to protect the stomach against the noxious effects of alcohol and other damaging agents, was measured. Gastric mucin was separated into soluble (washout) and insoluble (adherent) phases before colorimetric quantitation of total mucin, protein-bound hexose and sialic acid. Cysteamine produced a dose-dependent increase in release of soluble and gel mucin. Prostaglandin F2.beta. caused a dose-dependent release of hexose-containing mucin, but had no effect on sialic acid-containing glycoproteins. Sepharose 4B chromatography of both the soluble and adherent mucus revealed that > 90% was a high MW glycoprotein fraction. N-Ethylmaleimide, a known inhibitor of cytoprotection by cysteamine, had no effect on mucin secretion. Similarly, indomethacin inhibited mucin secretion by cysteamine but did not significantly influence cytoprotection. Thus, the secretion of mucin by cytoprotective agents is unlikely by itself to explain the ability of the stomach to resist chemical or physical damage.