Seasonal breeding as a neuroendocrine model for puberty in sheep

Jeremy Troy Smith, Iain James Clarke

Research output: Contribution to journalArticleResearchpeer-review

22 Citations (Scopus)

Abstract

Puberty is defined as the awakening of the hypothalamic-pituitary gonadal axis. Sheep are seasonal breeders, experiencing an annual period of reproductive quiescence and renaissance that can be utilized as a model for the onset of puberty. Kisspeptin and gonadotropin-inhibitory hormone appear to be important for the seasonal shift in reproductive activity and the former is mandatory for puberty. The non-breeding season is characterized by an increase in the negative feedback effect of estrogen on GnRH and gonadotropin secretion, as is the case in the pre-pubertal period. This effect of estrogen may be transmitted by kisspeptin cells. Additionally, dopaminergic A14/A15 neurons facilitate the seasonal change in estrogen negative feedback. Integrated function of these three groups of neurons appears to modulate the annual shift in photoperiod to a physiological change in fertility. This review compares and contrasts seasonal cycles of reproduction with the mechanisms that relate to the onset of puberty.
Original languageEnglish
Pages (from-to)102 - 109
Number of pages8
JournalMolecular and Cellular Endocrinology
Volume324
Issue number1-2
DOIs
Publication statusPublished - 2010

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