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ASSESSMENT OF THE HEPATOTOXICITY OF ACUTE AND SHORT-TERM EXPOSURE TO INHALED P-XYLENE IN F-344 RATS
Citation:
Simmons, J. ASSESSMENT OF THE HEPATOTOXICITY OF ACUTE AND SHORT-TERM EXPOSURE TO INHALED P-XYLENE IN F-344 RATS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-91/058 (NTIS PB91191650), 1991.
Description:
Because of the ubiquitous presence of p-xylene in air and the existing uncertainty regarding its hepatotoxic potential, we examined the effect of acute and short-term exposure to Inhaled p-xylene on the liver. ale F344 rats were exposed to 0 or to 1600 ppm p-xylene, 6 hr/day, for 1 or 3 days. xposure to inhaled p-xylene, either for 1 or for 3 days, caused no histopathological evidence of hepatic damage. onsistent with this lack of histological evidence of hepatotoxicity, p-xylene exposure had little or no effect on the serum levels of aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, ornithine carbamyl transferase, alkaline phosphatase and total bilirubin. xposure to p-xylene for 1, but not 3 days, resulted in an increase in absolute and relative liver weight. he concentration of hepatic cytochrome P-450 was increased by both p-xylene exposure regimens on the first day post-exposure. hese observations provide consistent evidence that acute and short-term exposure to 1600 ppm p-xylene by inhalation did not produce overt hepatotoxicity but resulted in a significant increase in the concentration of hepatic cytochrome P-450, the principal enzyme system involved in the metabolic biotransformation of xenobiotics.