Chlorobenzene-impaired lindane metabolism and the effect of pretreatment with chlorobenzene, lindane, or chlorobenzene plus lindane.

The storage and metabolism of lindane (gamma-HCH) was studied in the female rat after the administration of a hepatotoxic dose of chlorobenzene. Impaired lindane metabolism was observed following a challenge dose of 1.12 g chlorobenzene/kg. The data indicated that a hepatotoxic dose of chlorobenzene (CB) selectively impaired certain pathways, such as dehydrochlorination and the direct hydroxylation of lindane, to a greater extent than others, such as the dehydrogenation and dechlorination of lindane. Pretreatment with a subtoxic level of chlorobenzene produced: (1) significant increases in the dehydrogenation of lindane, (2) significant increase in the excretion of conjugated metabolites, (3) significant increases in the excretion of metabolites derived from the dehydrogenation of lindane through hexachlorocylohexene, gamma-HCCH, (4) significant improvement in the excretion of metabolites derived from CB-impaired dehydrochlorination of lindane as well as from the CB-impaired hydroxylation of lindane, and (5) significant reduction in the level of unaltered lindane stored in the adipose tissue. Repeated pretreatment with a subtoxic level of chlorobenzene offered significant protection against the reduction in lindane metabolism produced by the single hepatotoxic dose of chlorobenzene. Pretreatment with gamma-HCH alone was not as effective against the hepatotoxic effect of CB on lindane metabolism.