The role of the intestinal tract in the elimination of carbon tetrachloride.

The target organ toxicity, mechanisms of toxicity, and metabolism of carbon tetrachloride (CCl4) have been studied extensively. However, there is a paucity of information concerning its elimination. Previous inhalation studies showed that a significant amount of 14C appeared in the feces of rats and monkeys exposed to 14CCl4. The nature of the compound(s) excreted in the feces has not been well characterized. Fecal excretion is a major route of elimination for many lipophilic compounds that are resistant to metabolism. A mechanism of excretion for these compounds is the direct exsorption from the blood to the lumen of the intestinal tract. The primary purpose of this study was to determine if fecal elimination contributes significantly to the elimination of CCl4. The secondary purpose was to determine the mechanism (biliary and/or nonbiliary, i.e., direct exsorption) of fecal elimination of CCl4 and/or its metabolite(s) in Sprague-Dawley rats. The results indicate that both biliary and nonbiliary mechanisms contribute to the fecal elimination of CCl4 following a single iv dose (1 mmol/kg), but this route accounts for less than 1% of the administered dose. The results also indicate that CCl4 is not eliminated unchanged in the feces following either acute treatment (iv or ip) or repeated inhalation exposures. Fecal elimination of CCl4 does not significantly contribute to the overall elimination of CCl4.