[Specificity of cytochrome P-450 forms in the rat liver after inhalation of multicomponent hydrocarbon mixture]

Rats were inhaled with C6-C9 petroleum fraction 12 hrs daily for 9 days. The hydrocarbons and their metabolites gas chromatographic profiles from liver, kidney, brain and blood were investigated by means of head space technique. The observed characteristic profile composed of some hydrocarbons and secondary alcohols does not undergo qualitative changes and internal quantitative proportions remain constant in spite of cytochrome P-450 induction. Only total amount of hydrocarbons and their metabolites was varied. The results suggest that C6-C9 petroleum fraction inhalation does not induce new forms of cytochrome P-450 with different catalytic properties, but at the same time substrate binding site is modified to facilitate biotransformation of hydrocarbons and their metabolites.