Acidic glycolipids from kidney of suncus (Insectivora)

Lipids were extracted from the kidney of house musk shrew (Suncus murinus), which belongs to the order Insectivora. Acidic glycosphingolipids were purified from lipid extracts by mild alkaline methanolysis followed by column chromatographies on DEAE-Sephadex and silica beads (Iatrobeads). Purified glycolipids were analyzed by thin-layer chromatography, mild acid hydrolysis, gas liquid chromatography of the methyl glycosides after methanolysis and gas chromatography-mass spectrometry of the partially methylated alditol acetates. The kidney of suncus was unique in that it contained ganglioside GM2 (NeuAc type, 28.7 nmol and NeuGc type, 15.8 nmol/g tissue) as the major ganglioside. GM4 (NeuAc) (2.6 nmol/g), and GM3 (NeuAc type, 11.5 nmol and NeuGc type, 8.7 nmol/g) were also present. The content (298.9 nmol/g) of galactosyl sulfatide (GalCer-I3-sulfate) was higher than the values reported previously for other animal species. The total amount of acidic groups in glycolipids of suncus kidney was compared with the values for the kidney of 4 placental mammals to obtain an allometric correlation: log Y = 0.266 + 0.780 log X where X designates body weight, kg and Y, total acidic groups, mumol. A highly significant correlation (r = 0.999) was obtained among values from 5 representative placental mammals which live in mesic environments, suggesting that acidic glycosphingolipids are essential for the kidney function.