Effects of energy restriction on thyroid hormone metabolism in chickens

Andrea Gyorffy, Ahmed Sayed-Ahmed, Attila Zsarnovszky, Vilmos Frenyó, Eddy Decuypere, Tibor Bartha

Research output: Contribution to journalArticle

8 Citations (Scopus)


Energy restriction induces changes in thyroid hormone economy in the form of a complex adaptation mechanism, in order to conserve energy storage and protein reserves. In the present work, thyroid hormone serum concentrations, hepatic deiodinase enzyme activities and hepatic deiodinase mRNA expression were examined after feed restriction and fasting. We demonstrate that during energy restriction, T 3 concentration is lowered due to a decreased T 4 activation and increased T 3 inactivation. We show that hepatic type-I deiodinase (D1) is not affected by energy restriction, however, hepatic D2 is decreased on both transcriptional and enzyme activity levels. Furthermore, hepatic D3 is increased after feed restriction in the liver. We also show that the hypothalamic feedback is not involved in the changes in serum T 3 and T 4 concentrations. Our data indicate that D2 enzyme contributes to the special hormone-exporting role of the chicken liver and this enzyme can be modulated by feed restriction.

Original languageEnglish
Pages (from-to)319-330
Number of pages12
JournalActa veterinaria Hungarica
Issue number2
Publication statusPublished - Jun 1 2009


  • Chicken
  • Deiodination
  • Energy restriction
  • Liver

ASJC Scopus subject areas

  • veterinary(all)

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