Biochemical and behavioural effects of inhalation exposure to tetrachlorethylene and dichlormethane.

The exposure of adult male rats to 200 ppm of tetrachlorethylene t hours daily for 4 days resulted in a marked sequestration of solvent in perirenal fat 17 hours after the last exposure period. Similar exposure of similar rats to 500 ppm of dichlormethane led to a lesser accumulation of the solvent in fat as studied at the same time. Further exposures on the fifth day increased promptly the solvent contents of various organs. The exposure to tetrachlorethylene caused a diminished brain RNA content on the fifth day with simultaneous increase in the activity of non-specific cholinesterase. Similar changes in the RNA content were not seen in experiments with dichlormethane while the activity of acid proteinase increased above the control level in brain. Observations on the performance of the same animals in an open-field situation revealed that ambulation was affected in experiments with tetrachlorethylene immediately after exposure while preening pattern was changed after exposure to dichlormethane. Analysis on liver microsomal cytochrome P-450 content displayed slight increases in the hemochrome content in both experiments. The present data indicated that a rather modest exposure to both solvents could cause significant solvent accumulation in the fat and brain with marked effects on rat behaviour and protein metabolism in brain while changes in liver cytochrome P-450 content might not reflect the magnitude of these changes.