PROSTAGLANDIN E(2) ALTERS TERMINAL GLYCOSYLATION OF HIGH-MOLECULAR-WEIGHT GLYCOPROTEINS, RELEASED BY PIG GASTRIC MUCOUS CELLS IN-VITRO

The gastric mucus layer consists of high molecular weight glycoproteins (HMG). E-Type prostaglandins (PGs) stimulate total HMG release from isolated gastric mucous cells, We determined the effects of PGE(2) on HMG glycosylation. Pig gastric mucous cells were cultured for 20 h with 1 mu mol/l PGE(2). Released HMG were isolated by gel chromatography and periodic acid-Schiff (PAS)-positive sugars and protein-bound [C-14]GlcNAc were determined, Monosaccharides terminally linked to HMG oligosaccharide chains were monitored by lectin enzyme linked immunosorbent assay (ELISA): N-acetylglucosamine (GlcNAc) with Datura stramonium agglutinin, N-acetylgalactosamine (GalNAc) with soy bean agglutinin, fucose (Fuc) with Ulex europaeus I agglutinin and sialic acids (Sial) with Sambucus nigra agglutinin. PGE(2) stimulated total HMG release, indicated by an increase of PAS-positive sugars to 170% and [C-14]GlcNAc to 220% of controls, Terminal GlcNAc increased to 128%, GalNAc to 133%, Fuc to 165% and Sial to 182%. In addition to stimulation of total HMG release, PGE, caused alterations of HMG glycosylation, which may modulate HMG viscosity and microbiological barrier function.