Metabolism of brain and liver sulfatides.

The concentrations of lipid-solvent soluble sulfur in rat brain and liver have been reported by Gaitonde and Richter (2). The extraction procedure used by these authors resulted in lipid extracts containing nonlipid contaminants and proteolipid-proteins. Folch et al. (3, 4) have described methods for removal of these materials from lipid extracts. In the experiments to be reported, these methods of lipid purification were used. The sulfatide-sulfur was determined, after oxidation of the lipids, by the reduction method reported by Archer (5)) a method which circumvents the removal of phosphate necessary in the barium sulfate and benzidine sulfate methods (6,7). These experiments were set up to ascertain the role of age, species differences, dietary protein intake, and liver cell degeneration on the concentration and metabolism of brain and liver sulfatides. The present communication reports the detailed experiments which show incorporation in vivo of n-methionine-S35 and sulfateS35 into rat brain and liver sulfatides. The concentration of sulfatide-sulfur in the brain is a function of age; however, the specific activities decreased with age. The brain and liver sulfatide-sulfur concentration is dependent upon dietary protein intake. On the other hand, the liver sulfatide-sulfur concentration was unaltered in liver cell degeneration. The identity of the sulfatides has not been established. In this paper evidence is presented that two sulfatides are present in the lipid extracts from brain and liver by silicic acid chromatography.