Biliary mobilization of cadmium by 2,3-dimercaptopropanol and some related compounds.

No effective therapeutic agent for mobilizing tissue Cd has been reported to date, but the results presented here demonstrate that 2,3-dimercaptopropanol (BAL) , at doses approaching and surpassing the maximum tolerated, can produce a rapid transient enhancement of Cd excretion in the rat. When BAL (75 mg/kg) was administered by a single injection 24 h after a tracer dose of 109Cd, as much as 32% of the administered Cd appeared in the bile. A correlation between the appearance of radiocadmium and the biliary sulfhydryl concentration was found. There was indirect evidence for a 1:3 Cd-BAL complex in the bile, which may explain the efficacy of higher doses of BAL. A comparative study with some selected dithiol compounds suggests that vicinal sulfhydryl groups on an aliphatic chain are the more effective Cd mobilizing compounds, but BAL was the most effective agent. Although suspending vehicles alone showed no Cd mobilizing ability, the combination of BAL and oil was far superior to any other BAL-vehicle combination used. A spectrophotometric method for the determination of sulfhydryl groups in bile and urine is also presented.