Biosynthesis of neutral glycosphingolipids in kidney slices from male and female mice.

Previous reports from our laboratory (1981. J. Biol. Chem. 256: 13112-13120 and 1983. Endocrinology. 113: 251-258) showed the absence of Nfa-GalCer and Nfa-GaOse2Cer in kidneys of several strains of female mice. These lipids are always present in male kidneys and several other glycolipids are also elevated in males. To test whether this phenomenon is due to lowered biosynthesis in females, glycosphingolipid formation was assessed in kidney slices with [3H]galactose as precursor. The glycolipids were extracted after various incubation periods (from 30 min to 90 min) and individual glycolipids were separated and quantitated by high performance liquid chromatography and radioactivity was determined. The rate of formation of hydroxy fatty acid-containing galactosylceramide was the same in both sexes. The glycolipids which were low or not detectable in female kidney, Nfa-GalCer, Nfa-GaOse2Cer and Hfa-GaOse2Cer were rapidly labeled in the male kidney slices. These results suggest that nonhydroxy fatty acid-containing ceramide:UDP-Gal galactosyltransferase and hydroxy fatty acid-containing galactosylceramide:UDP-Gal galactosyltransferase have elevated activities in males. While the glucosylceramides are labeled at the same rates in both sexes, lactosylceramide appears to be labeled at higher rates in the male tissue. This suggests that glucosylceramide:UDP-Gal galactosyltransferase also has elevated activity in males. In addition, these data show that monohexosylceramides with different ceramide compositions are labeled at different rates.