Do gonadotrophin-releasing hormone neurons express estrogen receptors in the rainbow trout? A double immunohistochemical study.
A double immunocytochemical procedure, with two different chromogens, was used to compare the respective distributions of estrogen receptor-immunoreactive cells and gonadotrophin-releasing hormone-immunoreactive neurons on the same sections of the brains of adult male and female rainbow trout (Oncorhynchus mykiss). Estrogen receptor-immunoreactive cells were observed in the ventral and lateral telencephalon, the preoptic region, the mediobasal hypothalamus, and the ventromedial thalamic nucleus. Gonadotrophin-releasing hormone-immunoreactive perikarya were detected in the olfactory bulbs, the ventral telencephalon, the preoptic area, and the mediobasal hypothalamus. Double-staining studies showed that, although some estrogen receptor-positive cells were in close proximity to gonadotrophin-releasing hormone-immunoreactive perikarya, careful examination of 550 gonadotrophin-releasing hormone-positive cells from five adult females and two adult males failed to demonstrate any evidence that gonadotrophin-releasing hormone neurons coexpress estrogen receptor in the brain of the rainbow trout. The present study provides, for the first time in teleosts, morphological evidence that gonadotrophin-releasing hormone neurons do not represent major direct targets for estradiol, suggesting that the positive feedback effects of estradiol onto the gonadotrophin-releasing hormone system are likely to be conveyed via other cell populations.
Navas
J M
JM
Laboratoire de Neurocytochimie Fonctionnelle, URA, Talence, France.
Anglade
I
I
Bailhache
T
T
Pakdel
F
F
Breton
B
B
Jégo
P
P
Kah
O
O
D000818:Animals; D001345:Autoradiography; D001921:Brain / Q000166:cytology; D001923:Brain Chemistry / Q000502:physiology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D009474:Neurons / Q000378:metabolism*; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000096:biosynthesis*
D011960:Receptors, Estrogen; D007987:Gonadotropin-Releasing Hormone