Studies on Biological Activities of Melanin from Marine Animals. IV. Influence of Fr. SM II (Squid Melanin) on a High Molecular Glycoprotein (Peak I) Level in Rat Gastric Mucosa, and Properties of Peak I as a Gastric Mucosal Defensive Factor

Abstract

A low molecular weight melanoprotein from Ommastrephes bartrami LESUEL (Fr. SM II) has been reported to counteract the ulcer-inducing activities of phenylbutazone and aspirin. Glycoproteins extracted from the stomach were fractionated on a Sepharose 6B column and three peaks were obtained (peaks I, II and III). The amount of peak I was decreased following the onset of ulceration caused by phenylbutazone and aspirin, and was increased by a concomitant administration of Fr. SM II. The amount of lipid peroxide was found to reflect the degree of ulceration. The effect of peak I on lipid peroxidation was studied by incubating peak I with hepatic microsomes, arachidonic acid and gastric mucosa homogenate in vitro. The formation of lipid peroxide was inhibited by the addition of peak I. It was also demonstrated that peak I has a lysosomal membrane-stabilizing activity. These results suggest that Fr. SM II manifests its anti-ulcerogenic activity by increasing peak I.