In vitro release of gonadotropin-releasing hormone from the brain preoptic-anterior hypothalamic region and pituitary of female goldfish

1991 ◽  
Vol 81 (2) ◽  
pp. 256-267 ◽  
Author(s):  
K.L. Yu ◽  
P.M. Rosenblum ◽  
R.E. Peter
Keyword(s):  
In Vitro Release ◽  
Gonadotropin Releasing Hormone ◽  
Hypothalamic Region ◽  
Releasing Hormone ◽  
The Brain ◽  
Vitro Release

scholarly journals Live View of Gonadotropin-Releasing Hormone Containing Neuron Migration

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 463-468 ◽  
Author(s):  
Elizabeth P. Bless ◽  
Heather J. Walker ◽  
Kwok W. Yu ◽  
J. Gabriel Knoll ◽  
Suzanne M. Moenter ◽  
...  
Keyword(s):  
Real Time ◽  
Direct Evidence ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Reproductive Axis ◽  
Gnrh Neurons ◽  
Migratory Route ◽  
The Brain

Neurons that synthesize GnRH control the reproductive axis and migrate over long distances and through different environments during development. Prior studies provided strong clues for the types of molecules encountered and movements expected along the migratory route. However, our studies provide the first real-time views of the behavior of GnRH neurons in the context of an in vitro preparation that maintains conditions comparable to those in vivo. The live views provide direct evidence of the changing behavior of GnRH neurons in their different environments, showing that GnRH neurons move with greater frequency and with more changes in direction after they enter the brain. Perturbations of guiding fibers distal to moving GnRH neurons in the nasal compartment influenced movement without detectable changes in the fibers in the immediate vicinity of moving GnRH neurons. This suggests that the use of fibers by GnRH neurons for guidance may entail selective signaling in addition to mechanical guidance. These studies establish a model to evaluate the influences of specific molecules that are important for their migration.

Evidence that gonadotropin-releasing hormone (GnRH) functions as a prolactin-releasing factor in a teleost fish (Oreochromis mossambicus) and primary structures for three native GnRH molecules

1997 ◽  
Vol 155 (1) ◽  
pp. 121-132 ◽  
Author(s):  
GM Weber ◽  
JF Powell ◽  
M Park ◽  
WH Fischer ◽  
AG Craig ◽  
...  
Keyword(s):  
Gonadotropin Releasing Hormone ◽  
Sea Bream ◽  
Direct Effects ◽  
Gnrh Analog ◽  
Releasing Hormone ◽  
The Brain ◽  
Salmon Gnrh ◽  
Broad Role ◽  
Rostral Pars Distalis

Three forms of gonadotropin-releasing hormone (GnRH) are isolated and identified here by chemical sequence analysis for one species of tilapia, Oreochromis niloticus, and by HPLC elution position for a second species of tilapia, O. mossambicus. Of the three GnRH forms in O. mossambicus, chicken GnRH-II (cGnRH-II) and sea bream GnRH (sbGnRH) are present in greater abundance in the brain and pituitary than salmon GnRH (sGnRH). These three native forms of GnRH are shown to stimulate the release of prolactin (PRL) from the rostral pars distalis (RPD) of the pituitary of O. mossambicus in vitro with the following order of potency: cGnRH-II > sGnRH > sbGnRH. In addition, a mammalian GnRH analog stimulated the release of PRL from the pituitary RPD incubated in either iso-osmotic (320 mosmol/l) or hyperosmotic (355 mosmol/l) medium, the latter normally inhibiting PRL release. The response of the pituitary RPD to GnRH was augmented by co-incubation with testosterone or 17 beta-estradiol. The effects of GnRH on PRL release appear to be direct effects on PRL cells because the RPD of tilapia contains a nearly homogeneous mass of PRL cells without intermixing of gonadotrophs. Our data suggest that GnRH plays a broad role in fish, depending on the species, by affecting not only gonadotropins and growth hormone, but also PRL.

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