SELENIUM DETOXIFICATION BY METHYLATION

The major detoxification process for selenium is methylation. The majo r pathway for the formation of methylated compounds in biological syst ems is transmethylation catalyzed by methyltransferases. In this study methyltransferase activity was assayed in the liver cytosol prepared from different strains of rats using HPLC method by measuring the form ation of epinephrine from norepinephrine. The methyltransferase activi ty in Fischer, Wistar, and Sprague-Dawley rats were 1.65 x 10(-12), 0. 74 x 10(-12), and 1.2 x 10(-12) moles epinephrine formed/mg protein/hr respectively. Volatilization of injected Se (2.5 mg/kg, i.p.) was fou nd to be higher in Wistar rats compared to Fischer rats. LD(50) for Wi star and Fischer rats were 2.58 and 3.15 mg Se/kg respectively. Our re sults suggest that the methylation of dimethyl selenide to trimethyl s elenide appears to be an important step in the detoxification of selen ium.