Seasonal photoperiodism in vertebrates: from coincidence to amplitude

David Grey Hazlerigg, G C Wagner

Research output: Contribution to journalLiterature review

83 Citations (Scopus)


In vertebrates living in regions that range from tropical to polar zones, the day length (photoperiod) is a powerful synchronizer of seasonal changes in endocrine and metabolic physiology. This seasonal photoperiodism depends on the responses of internal circadian clocks to changing patterns of light-dark exposure, which can be conceptualized in the form of 'coincidence-timing' models. The structural basis for this timing function is formed by a specialized 'photoperiodic axis' that links light reception to the neurciendocrine system. In this review we describe the essential elements of this axis in mammals and birds, and discuss recent progress in understanding the cellular and molecular mechanisms through which this axis transduces photoperiodic change into altered endocrine output.

Original languageEnglish
Pages (from-to)83-91
Number of pages9
JournalTrends in Endocrinology and Metabolism
Publication statusPublished - 2006


  • gonadotropin-inhibitory hormone
  • MT1 melatonin receptor
  • pars tuberalis cells
  • Japanese quail
  • suprachiasmatic nucleus
  • gene expression
  • Syrian hamster
  • circadian rhythms
  • Siberian hamster
  • time measurement


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