Appearance in the blood plasma and excretion of 35S from three chemical forms of sulfur by lambs.

Abstract

Single doses of radioactive sulfur (35S) of three different chemical forms (elemental sulfur, sodium sulfate and methionine) were given orally via gelatin capsule to lambs. The lambs were also fed these same forms of supplemental sulfur prior to and following the administration of 35S. Radioactivity from sodium sulfate appeared in the plasma more rapidly than did radioactivity from methionine or elemental sulfur. Large amounts of 35S from sodium sulfate appeared in the plasma 1.0 hr. after dosing, while that from methionine and elemental sulfur appeared in largest amounts 42 to 54 hr. after the administration of the isotope. Lambs orally dosed with 35S-methionine had higher plasma isotope contents for the period from 36 to 192 hr. than plasma from lambs that received 35S-sodium sulfate or 35S-elemental sulfur. The similar time and pattern of appearance in plasma of 35S from elemental sulfur and methionine suggests that the sulfur from elemental sulfur which appeared in the plasma may have been incorporated into forms similar to those for methionine prior to absorption. These observations may also suggest similar sites of absorption. The major pathway of excretion of 35S from elemental sulfur and methionine was via the feces. Losses of 35S from sodium sulfate were about equally divided between feces and urine. During the 8 days following administration of the isotopes 8.52, 20.12 and 6.09% of the sulfur from elemental sulfur, sodium sulfate and methionine was lost in the urine. Fecal losses of 35S from the respective sources were 63.37, 21.77 and 20.39% of the administered doses.