A study of inhalation of pentachlorophenol by rats. IV. Distribution and excretion of inhaled pentachlorophenol.

It appears that in the rat repeated respiratory exposures to PCP do not result in an increase in the body burden of this compound as would be suspected from the 24 hour half-life determined from a single inhalation exposure. These results suggest some mechanism induced by prior exposure to PCP that increases the ability of the animals to remove this compound from its body. Increased excretion may be a factor in this activity, however, it cannot account for the total effect. Storage appears unlikely, since the elimination rate and time period remain unchanged after five doses as compared to after one. Increased matebolism may be the explanation, although this mechanism can only be inferred from these data. Quantitative metabolic results will be necessary to support this hypothesis.