The behavior of methylated selenium metabolites in the urine and in the expiration of rats which administered orally at various dosages (0, 0.31, 1.25 and 5.00 mg Se/kg diet) of selenite, was investigated. The contents of selenium in organs depended on the dose levels. Using Sephadex gel chromatograms of rat liver cytosols it was shown that at the toxic levels the amount of selenium more than that physiologically required for the active site of GSH-Px may bind to the other site. Excretions of trimethylselenonium ion (TMSe) in the urine and dimethyl selenide (DMSe) in exhaust gas increased with increasing accumulative levels of selenium. The excretion behaviors of TMSe and DMSe for 30 d after administration showed the same content level only at toxic dosage (average selenium intake level : 95μg Se/d). The present study suggested that as exposed by deficient to nutrient levels, selenium levels and GSH-Px activity in organs may be used to evaluate selenium level in the body, and the amount of TMSe in the urine and DMSe in exhaust gas may be utilized as indicators to predict the toxic selenium exposure level.
