Neuroendocrine mechanism of seasonal reproduction in birds and mammals
Article first published online: 21 JUL 2010
© 2010 The Author; Journal compilation © 2010 Japanese Society of Animal Science
Animal Science Journal
Volume 81, Issue 4, pages 403–410, August 2010
How to Cite
YOSHIMURA, T. (2010), Neuroendocrine mechanism of seasonal reproduction in birds and mammals. Animal Science Journal, 81: 403–410. doi: 10.1111/j.1740-0929.2010.00777.x
- Issue published online: 21 JUL 2010
- Article first published online: 21 JUL 2010
- Received 1 September 2009; accepted for publication 10 December 2009.
- pars tuberalis;
- mediobasal hypothalamus;
- thyrotropin (TSH);
- type 2 iodothyronine deiodinase (DIO2);
- thyroid hormone
In temperate zones, animals use changes in day length as a calendar to time their breeding season. However, the photoreceptive and neuroendocrine mechanisms of seasonal reproduction are considered to differ markedly between birds and mammals. This can be understood from the fact that the eye is the only photoreceptive organ, and melatonin mediates the photoperiodic information in mammals, whereas in birds, photoperiodic information is directly received by the deep brain photoreceptors and melatonin is not involved in seasonal reproduction. Recent molecular and functional genomics analysis uncovered the gene cascade regulating seasonal reproduction in birds and mammals. Long day-induced thyroid stimulating hormone in the pars tuberalis of the pituitary gland regulates thyroid hormone catabolism within the mediobasal hypothalamus. Further, this local thyroid hormone catabolism appears to regulate seasonal gonadotropin-releasing hormone secretion. These findings suggest that although the light input pathway is different between birds and mammals (i.e. light or melatonin), the core mechanisms are conserved in these vertebrates.