The Physiology of Puberty in Seasonally Breeding Birds
The neuroendocrine mechanisms regulating FSH secretion in birds are very similar to those in mammals, and the 400–600 GnRH cell bodies lie in the anterior hypothalamus, passing their axons in a broad band to end on the hypophysial portal vessels. Birds possess two forms of GnRH, but it is probable that only one of these (8-Gln-GnRH) is secreted from the median eminence: Like its mammalian counterpart, the bird stimulates the release of both FSH and LH. In male birds, FSH in conjunction with androgens causes spermatogenesis, while in females it triggers oogenesis and also aids yolk uptake from the circulation. It is still unknown what role the gonadotropins play in establishing and maintaining the characteristic hierarchy of oocytes within the avian ovary that allows for daily ovulations.
KeywordsRefractory State White Stork Gonadal Growth Testicular Mass Testicular Growth
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