Supplemental selenium alleviates the toxic effects of excessive iodine on thyroid.
As excessive iodine intake is associated with a decrease of the activities of selenocysteine-containing enzymes, supplemental selenium was hypothesized to alleviate the toxic effects of excessive iodine. In order to verify this hypothesis, Balb/C mice were tested by giving tap water with or without potassium iodate and/or sodium selenite for 16 weeks, and the levels of iodine in urine and thyroid, the hepatic selenium level, the activities of glutathione peroxidase (GSHPx), type 1 deiodinase (D1), and thyroid peroxidase (TPO) were assayed. It had been observed in excessive iodine group that hepatic selenium, the activities of GSHPx, D1, and TPO decreased, while in the groups of 0.2 mg/L, 0.3 mg/L and 0.4 mg/L supplemental selenium, the urinary iodine increased significantly. Compared with the group of excessive iodine intake alone, supplemental selenium groups had higher activities of GSHPx, D1, and TPO. We could draw the conclusion that supplemental selenium could alleviate toxic effect of excessive iodine on thyroid. The optimal dosage of selenium ranges from 0.2 to 0.3 mg/L which can protect against thyroid hormone dysfunction induced by excessive iodine intake.
Shenzhen Center for Chronic Disease Control, Shenzhen, 518020, People's Republic of China. anniexu73@hotmail.com
Jian
J
Xu
Xiao-Li
XL
Liu
Xue-Feng
XF
Yang
Huai-Lan
HL
Guo
Li-Na
LN
Zhao
Xiu-Fa
XF
Sun
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D007452:Iodates / Q000008:administration & dosage / Q000633:toxicity*; D007453:Iodide Peroxidase / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D017680:Potassium Compounds / Q000008:administration & dosage / Q000633:toxicity*; D018038:Sodium Selenite / Q000008:administration & dosage / Q000494:pharmacology*; D013961:Thyroid Gland / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D014867:Water
D007452:Iodates; D017680:Potassium Compounds; D014867:Water; D007453:Iodide Peroxidase; D005979:Glutathione Peroxidase; D018038:Sodium Selenite; C039693:potassium iodate