Evaluation of antioxidant status in liver tissues: effect of iron supplementation in experimental hyperthyroidism.
The antioxidant defense system in liver tissue in experimental hyperthyroidism and/or in iron supplementation was investigated. Thyroid hormones (T3, T4, TSH), ferritin (marker of iron status), antioxidant status components (glutathione [GSH], glutathione peroxidase [GSH-Px], superoxide dismutase [SOD]), and serum transaminases (GOT and GPT, both of which are known to be released from damaged hepatocytes), were measured. Hyperthyroidism in rats, induced by L-thyroxine administration, significantly raised SOD activity (p < 0.05), but significantly decreased GSH-Px activity and GSH values (p < 0.001) in the liver. In the L-thyroxine administered and iron supplemented (TI) group, GSH and GSH-Px values of liver tissues were significantly lower than those of control rats (p < 0.05). GSH-Px levels of the TI group were higher (p < 0.001), and SOD levels significantly lower (p < 0.001) than those of the L-thyroxine administered group. We conclude that hyperthyroidism induces SOD activity in liver; ferritin levels increase in hyperthyroidism, contributing to the antioxidant defense system; GSH-Px and GSH levels are decreased significantly in hyperthyroidism either due to inactivation due to increased oxidative stress or to insufficient synthesis; iron supple- and GPT analysis); iron decreases the effect of T4. This must be taken into consideration during iron supplementation.
Seymen
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Department of Physiology, Cerrahpasa Medical Faculty, Istanbul University, Turkey. seymano@yahoo.com
Seven
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Civelek
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Yiğit
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Hatemi
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Burçak
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D000818:Animals; D019587:Dietary Supplements; D005293:Ferritins / Q000097:blood; D005978:Glutathione / Q000032:analysis; D005982:Glutathione Transferase / Q000032:analysis; D006980:Hyperthyroidism / Q000378:metabolism*; D007501:Iron / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013482:Superoxide Dismutase / Q000032:analysis; D013963:Thyroid Hormones / Q000097:blood; D013974:Thyroxine / Q000633:toxicity
D013963:Thyroid Hormones; D005293:Ferritins; D007501:Iron; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D005978:Glutathione; D013974:Thyroxine