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Isotoxic oral and inhalation exposure of carbon tetrachloride in Porton–Wistar and Fischer rats

Male Fischer or Porton–Wistar rats were exposed for 4 h to different atmospheric concentrations of CCl4 or were given increasing oral doses of CCl4 in order to estimate isotoxic exposures or doses. Animals were killed 20 h after treatment, their serum glutamic–pyruvic transaminase activities were measured and their livers were processed for histological examination. It has been found that the equitoxic oral dose in Wistars is 1.5 times that in Fischer rats and more than 3 times after inhalation. Therefore, the conversion factors from inhalation exposure to oral dose were much higher for Fischer than for Porton–Wistar rats. After oral dosing, the extent of centrilobular damage in Fischer rats was approximately twice that in Porton–Wistar rats. After inhalation exposure, the extent of damage was the same in the two strains, but at least at the two lower exposure levels hydropic degeneration definitely contributed to the size of the damaged areas more in Porton‐Wistar than in Fischer rats.