The effect of melatonin on liver superoxide dismutase activity, serum nitrate and thyroid hormone levels

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Ozturk G., Coskun Ş., Erbas D., Hasanoglu E.

JAPANESE JOURNAL OF PHYSIOLOGY, vol.50, no.1, pp.149-153, 2000 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 50 Issue: 1
  • Publication Date: 2000
  • Doi Number: 10.2170/jjphysiol.50.149
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.149-153
  • Keywords: melatonin, nitrate, superoxide dismutase, thyroxine, triiodothyronine, NITRIC-OXIDE SYNTHASE, CYCLIC-GMP PRODUCTION, RAT, INHIBITION, DAMAGE, BRAIN, CELL
  • Gazi University Affiliated: Yes


Melatonin is a main neurohormone of the pineal gland. The effects of melatonin on the level of serum thyroid-stimulating hormone (TSH), thyroxine (T-4), triiodothyronine (T-3), nitrate, melatonin and liver superoxide dismutase (SOD) activity were examined in rats. Melatonin was injected at the dose of 10 mg/kg for 7 days, 2 h before turning the lights off. Rats were decapitated at 10:00 a.m, and 02:00 a.m., which are the times of the lowest and highest serum melatonin levels, respectively. Blood and tissue samples were collected. Decreased TSH, T-3, T-4 and nitrate levels were determined in the melatonin-injected and nighttime groups. Melatonin levels showed a diurnal rhythm. SOD activity increased in the melatonin-treated group. The results demonstrate that increased SOD activity, and reduced serum TSH, T-3, T-4 and nitrate levels correlated with the serum melatonin levels.