EN
The effect of ethanol and benzene and/or toluene on xylene biotransformation to methylbenzoic acid, was investigated in male Wistar rats exposed to solvents vapours by inhalation. One-, two-, and three-component solvent systems (xylene, xylene + benzene, xylene + toluene, xylene + benzene + toluene) at different concentrations ( 1.5,4.5, and 13.5 mmol/m3 of air), were used. The exposure was carried out in a dynamic toxicologic chamber for 4 succesive days, 6 hrs per day. Thirty minutes prior to every single experiment rats were treated by stomach tube with ethanol (aqueous solution) in a dose of 1366 or 2732 mg/kg body weight (1/10 or 1/5 LD50). The controls received distilled water only. Methylbenzoic acid concentration in the urine was measured within the first and the second day after termination of the exposure using gas chromatographic method. No effect of ethanol on urine elimination of methylbenzoic acid was observed in animals exposed to solvents vapours at the concentration of 1.5 mmol/ml of air. In animals exposed to solvents vapours at the concentration of 4.5 mmol/m3 and treated with ethanol at both dosing levels applied, a reduction of urine elimination of methylbenzoic acid amounting to from 34 to 40%, was noted. On the other hand, in animals exposed to solvents vapours at the concentration of 13.5 mmol/m3 and treated with ethanol in a dose of 1366 or 2732 mg/kg body weight, an increase of urine elimination of xylene metabolite form 25 to 58% in the first twenty-four hours, and from 89 to 300% in the second twenty-four hours, or from 48 to 107% and from 113 to 365%, respectively, was found. Results obtained allow for conclusion that reciprocal effects of ethanol and solvents vapours (at the concentration of 4.5 and 13.5 mmol/m3) on urine elimination of methylbenzoic acid, are in the nature of metabolic interactions between the xenobiotics used.