Seasonal regulation of reproduction: Altered role of melatonin under naturalistic conditions in hamsters

Matthew Butler, Kevin W. Turner, Jin Ho Park, Elanor E. Schoomer, Irving Zucker, Michael R. Gorman

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The seasonal reproductive cycle of photoperiodic rodents is conceptualized as a series of discrete melatonin-dependent neuroendocrine transitions. Least understood is the springtime restoration of responsiveness to winter-like melatonin signals (breaking of refractoriness) that enables animals to once again respond appropriately to winter photoperiods the following year. This has been posited to require many weeks of long days based on studies employing static photoperiods instead of the annual pattern of continually changing photoperiods under which these mechanisms evolved. Maintaining Siberian hamsters under simulated natural photoperiods, we demonstrate that winter refractoriness is broken within six weeks after the spring equinox. We then test whether a history of natural photoperiod exposure can eliminate the requirement for long-day melatonin signalling. Hamsters pinealectomized at the spring equinox and challenged 10 weeks later with winter melatonin infusions exhibited gonadal regression, indicating that refractoriness was broken. A photostimulatory effect on body weight is first observed in the last four weeks of winter. Thus, the seasonal transition to the summer photosensitive phenotype is triggered prior to the equinox without exposure to long days and is thereafter melatonin-independent. Distinctions between photoperiodic and circannual seasonal organization erode with the incorporation in the laboratory of ecologically relevant day length conditions.

Original languageEnglish (US)
Pages (from-to)2867-2874
Number of pages8
JournalProceedings of the Royal Society B: Biological Sciences
Volume277
Issue number1695
DOIs
StatePublished - Sep 22 2010
Externally publishedYes

Fingerprint

Photoperiod
melatonin
Melatonin
photoperiod
hamsters
Cricetinae
Reproduction
winter
Phodopus
day length
reproductive cycle
Natural History
rodent
Restoration
phenotype
Rodentia
natural history
Animals
Body Weight
regulation

Keywords

  • Melatonin
  • Season
  • Simulated natural photoperiod

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Environmental Science(all)
  • Immunology and Microbiology(all)
  • Medicine(all)

Cite this

Seasonal regulation of reproduction : Altered role of melatonin under naturalistic conditions in hamsters. / Butler, Matthew; Turner, Kevin W.; Park, Jin Ho; Schoomer, Elanor E.; Zucker, Irving; Gorman, Michael R.

In: Proceedings of the Royal Society B: Biological Sciences, Vol. 277, No. 1695, 22.09.2010, p. 2867-2874.

Research output: Contribution to journalArticle

Butler, Matthew ; Turner, Kevin W. ; Park, Jin Ho ; Schoomer, Elanor E. ; Zucker, Irving ; Gorman, Michael R. / Seasonal regulation of reproduction : Altered role of melatonin under naturalistic conditions in hamsters. In: Proceedings of the Royal Society B: Biological Sciences. 2010 ; Vol. 277, No. 1695. pp. 2867-2874.
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