An effect of sulfur nutrition on the metabolism of salicylamide.

The effect of supplementing diets containing 15% casein with inorganic sulfate and/or the sulfur-containing amino acids on the metabolism of salicylamide was determined. The glucuronide-salicylamide:sulfate-salicylamide (GS:SS) ratio in the urine of rats fed the diets containing 15% of casein without inorganic sulfate or sulfur containing amino acid supplementation approached unity. Addition of either 0.02% of inorganic sulfate or 0.625% of methionine reduced this ratio to approximately 0.3%. Addition of 0.325% of methionine or sufficient cysteine to be equimolar with 0.625% methionine did not lower the GS:SS ratio significantly. Therefore, it appears that not only the level but the source of sulfur may be important in the detoxication of drugs.