EFFECTS OF PEROXISOME PROLIFERATORS AND OR HYPOTHYROIDISM ON XENOBIOTIC-METABOLIZING ENZYMES IN RAT TESTIS/

The objectives of the present work were to study the effects of certai n peroxisome proliferators on xenobiotic-metabolizing enzyme activitie s in the testes of normal and hypothyroid rats, i.e. phenol sulfotrans ferases (pST), phenol UDP-glucuronosyl transferases (pUDPGT), glutathi one transferases (GST), catalase, epoxide hydrolase (EH), glutathione peroxidase (GPX) and NAD(P)H quinone oxidoreductase (QR). Adult male r ats (normal and hypothyroid) were treated for 10 days with clofibrate (0.5%), perfluorooctanoic acid (0.05%, PFOA), acetylsalisylic acid (1% , ASA) and di(2-ethylhexyl)phthalate (2%, DEHP) in their diet. The res ults show that treatment of normal rats with peroxisome proliferators dramatically affects the activities of xenobiotic-metabolizing enzymes (40-60% reduction). The highest effects are seen in catalase activity (50-60% with PFOA and ASA), pUDPGT (55% with PFOA), pST (55% with PFO A) and QR (50% with DEHP). These effects are not seen or are weaker af ter induction of hypothyroidism. Taken together, it is concluded that different classes of peroxisome proliferators have different effects o n rat testicular xenobiotic-metabolizing enzymes. (C) 1997 Elsevier Sc ience Ireland Ltd.