Photoperiodic regulation of retinoic acid signaling in the hypothalamus

Kirsty Deborah Shearer, Timothy Hugh Goodman, Alexander Ross, Laura Reilly, Peter John Morgan, Peter John Andrew McCaffery

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Both retinoic acid (RA) and thyroid hormone (TH) regulate transcription via specific nuclear receptors. TH regulates hypothalamic homeostasis and active T3 is generated by deiodinase enzymes in tanycytes surrounding the third ventricle. However, RA has not been previously considered in such a role. Data presented here highlights novel parallels between the TH and RA synthetic pathways in the hypothalamus implying that RA also acts to regulate hypothalamic gene expression and function. Key elements of the RA cellular signaling pathway were shown to be regulated in the rodent hypothalamus. Retinoid synthetic enzymes and the retinol transport protein Stra6 were located in the cells lining the third ventricle allowing synthesis of RA from retinol present in the CNS to act via RA receptors and retinoid X receptors in the hypothalamus. Photoperiod manipulation was shown to alter the expression of synthetic enzymes and receptors with lengthening of photoperiod leading to enhanced RA signaling. In vitro RA can regulate the hypothalamic neuroendocrine peptide adrenocorticotrophic hormone. This work presents the new concept of controlled RA synthesis by hypothalamic tanycytes giving rise to possible involvement of this system in endocrine, and possibly vitamin A, homeostasis.
Original languageEnglish
Pages (from-to)246-257
Number of pages12
JournalJournal of Neurochemistry
Volume112
Issue number1
Early online date26 Oct 2009
DOIs
Publication statusPublished - Jan 2010

Keywords

  • Animals
  • Cell Line
  • Cell Line, Tumor
  • Cells, Cultured
  • Hypothalamus
  • Male
  • Mice
  • Organ Culture Techniques
  • Photoperiod
  • Rats
  • Rats, Inbred F344
  • Rats, Sprague-Dawley
  • Receptors, Retinoic Acid
  • Signal Transduction
  • Thyroid Hormones
  • Transgenes
  • Tretinoin

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