EFFECTS OF PGE(2) AND OF DIFFERENT SYNTHETIC PGE DERIVATIVES ON THE GLYCOSYLATION OF PIG GASTRIC MUCINS

The glycosylation of pig gastric mucins, discharged in response to pro staglandin (PG) E-2 and to three synthetic PGE-derivatives (misoprosto l, nocloprost, rioprostil) was compared. After a 20 h culture period i n the absence or presence of 1 mu mol/l of one of the PGs, mucins were isolated by gel chromatography and their glycosylation characterized by their linkage to a panel of lectins. For all tested PGs, a signific antly increased lectin linkage to mucin glycoproteins of high molecula r weight was detected; no significant effects were observed for low mo lecular weight glycoproteins. Within the stimulatory pattern, major ef fects were found for the linkage of peanut agglutinin and soybean aggl utinin, suggesting predominant effects on the expression of galactose and N-acetyl-galactosamine. Only minor effects were found for sialic a cid, mannose, N-acetyl-glucosamine and fucose expression, as evidenced by the linkage of Sambucus nigra agglutinin, Concanavalin A, Datura s tramonium agglutinin and Ulex europaeus I agglutinin. All PGs exerted a similar stimulatory pattern. However, at the indicated concentration , misoprostol (281 +/- 36% of control) rendered a significantly higher overall effect than PGE(2) (208 +/- 31%), whereas the increases induc ed by nocloprost (237 +/- 35%) and rioprostil (202 +/- 35%) were not s ignificantly different from the PGE(2) effects. These results, suggest ing similar stimulatory effects of PGE(2) and of the tested synthetic PGs on glycosylation of mucin oligosaccharides, discharged from mucous cells during an in vitro culture, may, at least in part, explain clin ical findings that during an impairment of the endogenous PG synthesis , the tested synthetic PGs are effective exogenous substitutes for end ogenous E-type prostaglandins and act as anti-ulcer drugs.