Zinc Deficiency and Urinary Excretion of Taurine-35S and Inorganic Sulfate-35S Following Cystine-35S Injection in Rats

Abstract

The effect of zinc deficiency on cystine oxidation was studied by comparing the amounts of labeled 35S found in urinary inorganic sulfate and taurine following injection of cystine-35S into zinc-deficient and zinc-supplemented rats. The results show that rats receiving a diet low in zinc for 1 week excreted significantly more 35S than control animals. At the end of 3 weeks the recovery of injected 35S in the urine of zinc-deficient rats was three to four times greater than that of zinc-supplemented controls. This increase was due to zinc deficiency per se rather than to a reduction of food consumption, and disappeared upon zinc repletion. It was further demonstrated that the bulk of the excess sulfur found in the urine of rats following zinc deficiency was due to increased amount of both inorganic sulfate and taurine. Zinc-deficient rats also significantly increased the urinary excretion of 35S and 35SO42- after injection of 35S-labeled methionine, thiamin, thiourea and inorganic sulfate. Liver ATP sulfurylase was not affected by zinc deficiency indicating that zinc-deficient rats were capable of converting inorganic sulfate to its active form.