An Effect of Dietary Sulfate in Rats Fed Diets Low in Sulfur Containing Amino Acids

Seven diets which were low in sulfur containing amino acids but with inorganic sulfate from 0.0002 percent to 3.130 percent in system­ atic increases were fed to rats. The sulfur as sulfate in freeze-dried and combusted lungs and livers of these rats was determined. The data obtained showed a significant difference in both the amount of total sulfur in the lung as sulfate and the sulfur per mg. of dried lung. However, no significant difference was found in the total sulfur as sulfate in the liver or sulfur as sulfate per mg. of .dried liver. Since there is a high percentage of cartilaginous material in the lungs, it is reasonable to assume there is more mucopolysaccharide sulfur in the lung than in the liver and that the effect of increased mucopolysaccharide sulfation could be masked when the total liver sul­ fate was measured, but not in the lung. Based on previous data obtained from this laboratory, the increase in lung sulfate was interpreted as a reflection of increased synthesis of mucopolysaccharides. The sulfate content of the lungs obtained in this investigation shows quite conclusively that before dietary sulfate additions will give a measurable effect on retention of sulfate by the tissues, greater than approximately 0.1 percent sulfate should be added to the diet.