Thyrotropin-releasing hormone phase shifts circadian rhythms in hamsters

Keith A. Gary, Patricia J. Sollars, Nedra Lexow, Andrew Winokur, Gary E. Pickard

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


The role of thyrotropin-releasing hormone (TRH) in regulating circadian rhythms was investigated by assessing the ability of TRH microinjections into the suprachiasmatic nucleus (SCN) to induce phase shifts in hamster wheel-running behavior. TRH injected into the SCN at 10 and 100 nM doses produced phase advances in wheel-running activity of 18.3 ± 1.9 and 34.8 ± 2.9 minutes, respectively, when administered at circadian time (CT) 6. Injections at CT 18 produced no effects. The temporal sensitivity of the SCN to TRH administration was examined by administering TRH at specific circadian times. TRH produced significant phase advances at CT 4, 6, and 8, while no significant changes in wheel-running onset were observed at other CT times. These studies represent the first evidence of TRH's ability to affect circadian function.

Original languageEnglish (US)
Pages (from-to)1631-1634
Number of pages4
Issue number10
StatePublished - 1996
Externally publishedYes


  • Arousal
  • Oscillator
  • Protirelin
  • Suprachiasmatic
  • TRH

ASJC Scopus subject areas

  • Neuroscience(all)

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