title: Pinealectomy inhibits antioxidant system in rats with hyperthyroidism.
abstract: OBJECTIVE
  Thyroid hormones regulate energy metabolism and act on the mitochondria, which is an important source of free radicals in the cell. Reactive oxygen types play a significant role in physiological mechanisms, but in excessive amounts they can cause oxidative damage in molecules. The aim of the present study was to determine levels of lipid peroxidation caused by induced hyperthyroidism in cerebral, hepatic and cardiac tissues of pinealectomized rats.
  
  
  METHODS
  Experimental animals used in the study were allocated to three groups as general control group, hyperthyroidism-sham pinealectomy group and hyperthyroidism-pinealectomy group. GSH and MDA levels in cerebral, hepatic and cardiac tissues were evaluated at the end of the 3-week study period.
  
  
  RESULTS
  It was found that MDA levels in cerebral, hepatic and cardiac tissues were the highest in hyperthyroidism and pinealectomy group and that these values were higher in hyperthyroidism-sham pinealectomy group than in the control group (p<0.001). It was seen that tissue GSH levels significantly increased in hyperthyroidism-sham pinealectomy group (p<0.001) and that the increase in hyperthyroidism and pinealectomy group was higher than the increase in the control group only (p<0.001).
  
  
  CONCLUSIONS
  Results of our study show that MDA and GSH levels in cerebral, hepatic and cardiac tissues increased due to hyperthyroidism and that the increase in MDA levels became more evident and GSH levels were significantly suppressed after pinealectomy.
authors.affiliation: Department of Physiology, Meram Medical School, Selcuk University, 42080 Konya, Turkey. mogulkoc@selcuk.edu.tr
authors.forename: Rasim
authors.initials: R
authors.lastname: Mogulkoc
authors.forename: Abdulkerim Kasim
authors.initials: AK
authors.lastname: Baltaci
authors.forename: Leyla
authors.initials: L
authors.lastname: Aydin
authors.forename: Esma
authors.initials: E
authors.lastname: Oztekin
authors.forename: Abdullah
authors.initials: A
authors.lastname: Sivrikaya
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001921:Brain / Q000201:enzymology; D005978:Glutathione / Q000378:metabolism; D006980:Hyperthyroidism / Q000378:metabolism*; D015227:Lipid Peroxidation / Q000502:physiology*; D008099:Liver / Q000201:enzymology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology; D010870:Pineal Gland / Q000502:physiology* / Q000601:surgery; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000975:Antioxidants; D008315:Malondialdehyde; D005978:Glutathione