Alterations in Cerebral Xenobiotic-Metabolizing Enzymes in Iodine and/or Selenium Deficient Rats
Pinar ERKEKOGLU, Belma Kocer-GÜMÜŞEL, Aydan CAGLAYAN, Filiz HINCAL°

Department of Toxicology, Faculty of Pharmacy, Hacettepe University, Ankara 06100, TURKEY
° Corresponding Author E-mail: bgiray@hacettepe.edu.tr; fhincal@hacettepe.edu.tr

Summary
The aim of this study was to investigate the effects of iodine and/or selenium deficiency on cerebral enzyme levels/ activities responsible for xenobiotic metabolism on rats. Three-week old male Wistar rats were used and feeding period was 7-weeks. Selenium deficiency was introduced by a diet containing <0.005 mg/kg selenium, and iodine deficiency was produced by sodium perchlorate containing drinking water. The levels of total microsomal cytochrome P450 (CYP450) and cytochrome b5 (CYP b5) as well as the activities of microsomal NADPH-cytochrome P450 reductase (P450R), aniline hydroxylase (CYP2E1), and cytosolic glutathione S-transferase (GST) were determined. Significant decreases in CYP2E1 activity of iodine deficient, and combined iodine/selenium deficient groups, and marked increase in P450R activity of selenium deficient animals were observed. The generated data suggested that cerebral xenobiotic metabolizing system was affected by the iodine and/or selenium deficiency states which might alter the pharmacological response of central nervous system acting drugs and other xenobiotics in rats.

Key Words :
Iodine deficiency, selenium deficiency, combined iodine and selenium deficiency, thyroid hormones, xenobiotic metabolizing enzymes, cytochrome P450 enzymes