Protection against chronic cadmium toxicity by glycine

A Japanese drug containing glycine, glycyrrhizin, and cysteine (Stronger Ne o-Minophagen C(R)) has been reported to protect against chronic cadmium (Cd ) toxicity. The present study was conducted to evaluate which of the three constituents of this drug was the main antagonist for Cd toxicity and wheth er the mechanism of protection involved antioxidant action. Adult female Sp rague-Dawley rats were injected sc with 5 mu mol CdCl2/kg per day, five tim es per week, for 15 weeks. Four groups of Cd-injected animals received co-t reatments with either 10 mg glycyrrhizin/kg, 100 mg glycine/kg, 5 mg cystei ne/kg, or with a mixture of all three compounds, five times per week, start ing from week 7. An additional Cd-injected group was co-treated with vitami n E (100 mg/kg, five times per week, starting from week 7) as a positive co ntrol. Only those animals that received vitamin E, Minophagen mixture, or g lycine were protected against Cd-induced hepatotoxicity as well as nephroto xicity. All three co-treatments suppressed Cd-induced hepatic and renal lip id peroxidation. We conclude that the reported beneficial effects of Strong er Neo-Minophagen C(R) are due to glycine, which appears to protect against chronic Cd toxicity by reducing oxidative stress. (C) 1999 Elsevier Scienc e Ireland Ltd. All rights reserved.