Comparative disposition and elimination of chlordane in rats and mice

The absorption, distribution and elimination of orally administered cis-[14C]chlordane (1.0 mg/kg) was determined in male Sprague-Dawley rats and C57BL/6JX mice. Absorption appeared somewhat slower in mice, but total [14C]chlordane equivalents at peak blood concentration (113 ng/ml at 8 h) exceeded the maximum which occurred in rats (81 ng/ml at 2 h). Peak tissue residues in both species were observed within 4 h, suggesting that the radiocarbon responsible for the latent peak blood levels in mice was eliminated rather than sequestered by the tissues. This was supported by the findings that peak tissue residue levels were lower in mice, and that the initial fecal elimination rate was higher than in rats. At 12 h, 34% and 7% of the doses were excreted in mouse and rat feces, respectively; by 3 days, both species had voided 83% of the dose in the feces. Clearance rates of tissue residues were markedly faster in the rat, and consequently, the total body burden resulting from chronic exposure to chlordane will be far greater in mice than in rats.