Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2005, 149(2):329-333 | DOI: 10.5507/bp.2005.052

Effect of long-term administration of arsenic (III) and bromine with and without selenium and iodine supplementation on the element level in the thyroid of rat

Dana Kotyzová^a, Vladislav Eybl^a, Martin Mihaljevič^b, Eystein Glattre^c

^a Department of Pharmacology and Toxicology, Charles University in Prague, Faculty of Medicine in Pilsen, Pilsen, Czech Republic

^b Charles University, Faculty of Science, 120 00 Prague, Czech Republic

^c Cancer Registry of Norway, N-0310, Oslo, Norway

The aim of this study was to evaluate the influence of arsenic and bromine exposure with or withour iodine and selenium supplementation on the element level in the thyroid of rats. Four major groups of Wistar female rats were fed with respective diets: group A - standard diet, group B - iodine rich diet (10 mg I/kg food), group C - selenium rich diet (1 mg Se/kg) and group D - iodine and selenium rich diet (as in group B and C). Each group was divided into four subgroups per 7 animals each receiving either NaAsO₂ ip (6.5 mg.kg^-1 twice a week for two weeks and 3.25 mg.kg^-1 for six weeks) or KBr in drinking water (58.8 mg.l^-1) for 8 weeks or combined administration of both substances. Remaining subgroup served as controls. After 8 weeks thyroid glands were analyzed by ICP-MS for As, Br, Se, and I content. The exposition of rat to arsenic or bromine causes the accumulation of these elements in the thyroid gland (∼18 ppm of As, ∼90 ppm of Br) and significantly affects iodine and selenium concentration in the thyroid. In iodine and/or selenium supplemented rats the bromine intake into the thyroid was lowered to ∼50% of the level in unsupplemented animals. Also selenium thyroid level elevated due to KBr administration was lowered by iodine supplementation in the diet. The accumulation of arsenic in the thyroid was not influenced by selenium or iodine supplementation; however, As(III) administration increased iodine thyroid level and suppressed selenium thyroid level in selenium or iodine supplemented group of animals.

Keywords: Iodine, Thyroid gland, Selenium, Bromine, Arsenic

Received: June 10, 2005; Accepted: September 25, 2005; Published: December 1, 2005  Show citation