Studies on pharmacological activation of human serum immunoglobulin G by chemical modification and active subfragments. III. Mechanism of anti-ulcerous action of alkylated light chain (Fr. I-L).

Abstract

The effects of a new anti-ulcer agent Fr. I-L, a reduced and carboxamide-methylated light chain of human immunoglobulin G, on defensive factors in gastric mucosa were studied. Fr. I-L increased the mucopolysaccharide contents (hexosamine, uronic and sialic acids) in the gastric mucosa of intact rats and inhibited the decrease of mucopolysaccharide contents in the gastric mucosa of rats with phenylbutazone-induced gastric ulcers. The activation of the biosynthesis of mucopolysaccharides by Fr. I-L was suggested by tracing the incorporation of 35SO4(2-) into the gastric mucosa. The administration of aspirin or phenylbutazone caused an increase of mucopolysaccharase activity in the gastric mucosa and the concomitant administration of Fr. I-L blocked the elevation of the enzyme activities. Fr. I-L also showed inhibitory activities on the local fibrinolysis and lipid peroxidation in the gastric mucosa.