Comparative study of the metabolic fate of selenate, selenite, and sulfate ions in cartilage

In vivo injections of three types of anions (75SeO3=, 75SeO4=, 35SO4=) into rabbits revealed a basic difference between the metabolic behavior of the selenium anions and that of sulfur anion in cartilage; whereas sulfate was incorporated predominantly into glycosaminoglycans, the entry of both selenium ions into this fraction was almost nonexistent. On the other hand, protein and lipid fractions isolated from cartilage had higher activity levels when selenium ions were injected than when sulfate was injected. In cartilage, the selenate activity disappeared at a faster rate than either selenite or sulfate. In blood sera the rate of activity disappearance was higher with both selenate and sulfate than with selenite.