Increasing gonadotropin-releasing hormone release by perifused hypothalamus from early to late anestrus in the beagle bitch.
An in vitro perifusion system was used to investigate pulsatile gonadotropin-releasing hormone (GnRH) release from hypothalamic fragments derived from beagle bitches at different stages of the estrous cycle. The spontaneous GnRH release from the excised tissue fragments that include the "mediobasal hypothalamic-preoptic area-suprachiasmatic nucleus units' was episodic throughout all stages of the estrous cycle with a significantly high release rate during late anestrus and late proestrus. The GnRH release rate and plasma levels of luteinizing hormone were positively correlated (r = 0.94, P < 0.01). These results suggest that during the course of anestrus in the bitch the GnRH release rate increases while the pituitary responds accordingly.
Tani
H
H
Department of Animal Reproduction, College of Agriculture, University of Osaka Prefecture, Japan.
Inaba
T
T
Tamada
H
H
Sawada
T
T
Mori
J
J
Torii
R
R
D000818:Animals; D004285:Dogs; D004971:Estrus / Q000502:physiology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000097:blood
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone