Acta Biologica Hungarica

, Volume 58, Issue 4, pp 335–343 | Cite as

Pinealectomy and Melatonin Administration in Rats: Their Effects on Plasma Leptin Levels and Relationship with Zinc

  • A. K. BaltaciEmail author
  • R. Mogulkoc


The aim of this study was to examine effects of pinealectomy and melatonin administration plasma leptin levels and its relationship with zinc in rats. The study was conducted on 40 adult male Sprague-Dawley rats. They were divided into four groups each containing 10 animals. Group 1 served as control. Group 2 was pinealectomized group. Animals in Group 3 were pinealectomized and injected with melatonin (3 mg/kg/day, ip). Group 4 received melatonin alone (3 mg/kg/day, ip). At the end of the experiments, all animals were decapitated and trunk blood collected. Plasma leptin and zinc levels were determined by radioimmunoassay and Atomic Absorption Spectrophotometer methods, respectively. Although mean weights of the animals at the beginning were not significantly different among the groups, the mean weight of the pinealectomized group was found to be significantly lower than all other groups at the end of a six-month period (p < 0.01). Plasma leptin and zinc levels were the highest in mela-tonin-administered group (group 4; p < 0.01). The lowest plasma leptin and zinc levels were obtained in the pinealectomized group (group 2; p < 0.01). Changes in these two parameters were not statistically significant in groups 1 and 3. Our findings indicate that pinealectomy results in a decrease in leptin and zinc levels in rats, and that melatonin administration to pinealectomized rats prevents the decrease in the these parameters. In addition, long-term administration of melatonin to rats leads to an increase in both leptin and zinc concentrations.


Pinealectomy melatonin administration leptin zinc 


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Supported in part by a Research Fund of Selcuk University Grant no: TF 2001/045. We would like to thank to Dr. Bayram Yilmaz of Firat University Medical School for his critical evaluation and English correction of the manuscript.


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© Akadémiai Kiadó, Budapest 2007

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Authors and Affiliations

  1. 1.Department of Physiology, Meram Medical SchoolSelcuk UniversityKonyaTurkey

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