Glycolipids of the fish testis

Abstract

Glycolipids were purified from the total lipid extract of the testis or milt of a kind of puffer (Fugu rubripes rubripes) by adsorption column chromatography using silicic acid and magnesium silicate and by preparative silica gel TLC. The glycolipids were identified as glucosylceramide (116 mug/g wet tissue) and galactosylceramide 26.7 mug/g). Seminolipid, a sulfagalactolipid specific to mammalian testis was not detected, but the presence of a small amount of sulfatide (15.2 mug/g) was demonstrated. The long-chain bases of both cerebrosides were mainly C18-sphingenine, but in sulfatide, C20-sphingenine was more abundant than C18-sphingenine. In both cerebrosides and sulfatide, the fatty acid compositions were similar, with nervonic acid as the predominant component. Two species of gangliosides were also obtained and were identified as N-acetylgalactosaminyl(1 leads to 4)[N-acetylneuraminyl(2 leads to 3)]galactosyl(1leads to 4)glucosylceramide (59.8 mug/g) and N-acetylneuraminyl(2 leads to 3)galactosyl(1 leads to 4)N-acetylglucosaminyl(1 leads to 3)galactosyl(1 leads to 4)glucosylceramide (45.0 mug/g). The long-chain bases of the two gangliosides consisted of C18-spingenine and C20-sphingenine, and the major fatty acids were palmitic and stearic acids.