The Novel Gonadotropin-releasing Hormone (GnRH) of Fish: Its Functions, Regulation of Synthesis and Release, and Potential Use for Spawning Manipulations in Striped BassThe farming of striped bass and other fish species in Maryland and the mid-Atlantic has been expanding in the last decade; nevertheless, the economic growth will remain limited unless growers can have access to inexpensive seed, i.e., embryos or newly hatched fish. Though large striped bass have been maintained and spawned in hatcheries, their captivity more often than not disrupts hormonal systems. Consequently, growers have had to depend on the capture of gravid striped bass for eggs and sperm; they then inject the fish with a hormone to induce spawning. These are costly processes. If the industry is to significantly step up production, growers will need to obtain eggs on demand so that they can reliably plan and predict their production and harvest cycles. With continuing Sea Grant-support, Yonathan Zohar has significantly enhanced our understanding of the molecular processes controlling the pituitary gland and its release of growth hormones. Recent studies led to the important discovery of a maturational gonadotropin that regulates the final ovarian development and may be the major hormone responsible for egg and sperm development. In captivity, it is this gonadotropin that is blocked so that it is not released to the blood stream and does not reach the ovaries. Yonathan Zohar's research on the molecular processes controlling the pituitary gland and its release of growth hormones has led to the important discovery of a maturational hormone that regulates final ovarian development. Unlike the situation in the wild, confinement affects the gonadotropin-releasing system, so that the hormone is blocked from the bloodstream and, therefore, does not reach the ovaries. In this project, Zohar will continue to refine chemical analogs of the newly discovered gonadotropin to improve spawning induction in striped bass. In addition, he will detail the regulation and release of this growth hormone and thereby help explain reproductive failures in captive fish. |
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1998-1999
Yonathan Zohar Center of Marine Biotechnology University of Maryland Biotechnology Institute 1996-1997 Yonathan Zohar Center of Marine Biotechnology University of Maryland Biotechnology Institute Thomas T. Chen University of Connecticut Biotechnology Center |
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