SUBCHRONIC TOXICITY OF A MEDIUM-CHAIN CHLORINATED PARAFFIN IN THE RAT

Groups of ten male and female weanling Sprague-Dawley rats were fed di et containing 0, 5, 50, 500 or 5000 ppm of a medium-chain chlorinated paraffin (C-14-17, 52% chlorination) for a period of 13 weeks, Increas ed relative liver weight was observed at 500 and 5000 ppm in females a nd at 5000 ppm in males, Relative kidney weight was increased at 5000 ppm in both sexes, Serum cholesterol was increased in the females in a dose-related manner starting at 50 ppm, At 5000 ppm, animals of both sexes had elevated hepatic UDP-glucuronosyltransferase activity while only females showed increased aminopyrine N-demethylase activity. Incr eased urinary N-acetylglucosaminidase activity occurred at 5000 ppm in females, Increased urinary ascorbic acid excretion monitored at week 12 and a decreased hepatic vitamin A level were detected in females re ceiving the 500 ppm diet and male and female rats at 5000 ppm. Mild, a daptive histopathological changes were detected in the liver of rats o f both sexes at 500 and 5000 ppm, and in the thyroid of males and fema les starting at 500 and 50 ppm, respectively, Minimal changes were obs erved in the kidney proximal tubules of male rats fed the 5000 ppm die t and in the inner medulla tubules of female rats fed the 500 and 5000 ppm diets, These data indicate that the medium-chain chlorinated para ffin produces biochemical and histological changes at dietary levels o f greater than or equal to 50 ppm in females and greater than or equal to 500 ppm in males.