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Fish Reproduction - Anatomy & Physiology (view source)
Revision as of 13:25, 29 July 2008
, 13:25, 29 July 2008→Reproductive Endocrinology
* GnRH travels from the hypothalamus to the pituitary gland.
* GnRH travels from the hypothalamus to the pituitary gland.
* Gonadotroph cells of the pituitary receive GnRH and release gonadotropic hormones into the bloodstream.
* Gonadotroph cells of the pituitary receive GnRH and release gonadotropic hormones into the bloodstream.
** '''GTH-I''' has FSH-like activity.
** '''GTH-II''' has LH-like activity.
* The gonadotropic hormones travel to the gonads, which synthesize steroids responsible for final maturation of the gametes.
* The gonadotropic hormones travel to the gonads, which synthesize steroids responsible for final maturation of the gametes.
** GTH-I binds to theca and granulosa cells of follicles. This induces testosterone production by theca cells. Testosterone then travells to the granulosa cells, where it is converted to oestrogen (as in mammals). Oestrogen induces vitellogenin production in the liver.
** GTH-II binds to granulosa cells and induces production of progestins.
* Maturation of the egg is a long process that involves complex physiological and biochemical changes. One important step, vitellogenesis, is a process in which yolk proteins are produced in the liver, transported to the ovary, and stored in the egg, resulting in tremendous egg enlargement. The yolk is important as a source of nutrition for the developing embryo.
* Maturation of the egg is a long process that involves complex physiological and biochemical changes. One important step, vitellogenesis, is a process in which yolk proteins are produced in the liver, transported to the ovary, and stored in the egg, resulting in tremendous egg enlargement. The yolk is important as a source of nutrition for the developing embryo.
* Also critical are germinal vesicle migration and germinal vesicle breakdown (GVBD).
* Also critical are germinal vesicle migration and germinal vesicle breakdown (GVBD).