The Utilization of the Sulfur of Sulfolipid by the Albino Rat

35S-sulfolipid was isolated from weanling rat brains and incorporated into a diet which was fed to rats for a period of nine days during which time urine and feces were collected daily in the initial study and continuously during the second phase of the study. The 35S-sulfur from the sulfolipid was poorly absorbed, 20 percent of the ingested dose was excreted in the urine and 55 percent in the feces. The amount of radiation excreted in the urine plateaued after the third day with no significant difference occurring until the ninth day when there was a 96 percent increase in urinary excretion and a 63 percent decrease in fecal excretion, suggesting an adaptation in absorption of sulfolipid. Since approximately 75 percent of the ingested dose could be accounted for in excretory products only a small percentage would be available for tissue utilization. It seems unlikely that sulfolipid in a diet could serve as an effective source of exogenous sulfur in view of the poor absorption, the high excretion, and the lack of significant retention by the tissue, including the cartilage mucopolysaccharides. When the uptake of 35S by the cartilage mucopolysaccharides was expressed in counts per minute per mMS04 as percent of dose, it was noted that the specific activity was very high and it is thought that some method may exist of selectively incorporating the sulfate of sulfolipid into mucopolysaccharides. Although it seems unlikely that exogenous sulfolipid can serve as a source of sulfur for an animal, it may exert a significant influence on the sulfation of mucopolysaccharides without contributing to the sulfate pool. Attempts made to identify the metabolites in the urine, indicate the presence of a galactose - 3 - 35SO4