[Effect of trichloroethylene on metabolism and toxicology of benzene in rats].

The effect of trichloroethylene treatment on the metabolism of benzene in vivo, and on the benzene-induced hemotoxicity, was investigated. Male Wistar rats were injected subcutaneously with benzene at 0, 2.5, 5.0, 10.0 or 20.0 mmol/kg daily for 5 days. Other rats were treated with a mixture of benzene and trichloroethylene at the same doses in a molar ratio 1:1, 1:2, and 1:05. Before, during and after exposure, both total number of leukocytes and lymphocytes in peripheral blood and excretion rate of phenol in urine (free and conjugated) were measured. In rats treated with benzene alone excretion rates of both free and conjugated phenol were elevated but not proportionally with the dose of benzene. After administration of this compound at 20.0 mmol/kg increase of free phenol excretion in successive days which was correlated with number of lymphocytes in peripheral blood were observed. Biotransformation of benzene to free and conjugated phenol was suppressed by co-administration of trichloroethylene, but occasionally it was stimulated. The changes in peripheral blood corresponded well with excretion rate of free phenol in urine. Probable mechanisms of these observations were discussed.