Immunohistochemical localization of chicken gonadotropin-releasing hormones I and II (cGnRH I and II) in turkey hen brain.
The distribution of cells and fibers immunoreactive (ir) for either chicken gonadotropin-releasing hormone I (cGnRH I; [Gln8]GnRH) or II ([His5,Trp7,Tyr8]GnRH) was determined in brains of turkey hens to reveal whether these peptides occur in separate neuronal systems. ir-cGnRH I cells were located: along the medial aspect of the ventriculus lateralis, nucleus accumbens, and bed nucleus of the stria terminalis; ventral to the tractus septomesencephalicus and extending medially to the third ventricle, and caudally into the lateral hypothalamic area; and in a diffuse band extending from the nucleus preopticus medialis to the nucleus dorsomedialis anterior thalami. cGnRH I fibers were evident in these areas in addition to the hippocampus, nucleus subhabenularis medialis, nucleus ventromedialis hypothalami, and median eminence. Two groups of ir-cGnRH II cells were observed: a magnocellular group lying between the substantia grisea centralis and the nucleus ruber; and a parvicellular group lying medial to the nucleus of the basal optic root and extending into the lateral hypothalamic area. ir-cGnRH II fibers were prominent in limbic structures (cortex piriformis, lateral to nucleus taeniae, hippocampus); olfactory areas (tuberculum olfactorium, nucleus subhabenularis lateralis, nucleus septalis lateralis); areas that in other avian species have steroid-concentrating cells or receptors (medial edge of lobus parolfactorius, nucleus septalis medialis, nucleus periventricularis magnocellularis, nucleus dorsomedialis posterior thalami); and areas containing ir-GnRH I cells or fibers but not in median eminence. These results suggest that cGnRH I and II occur in separate neuronal systems and that cGnRH II does not directly promote pituitary gonadotropin secretion.
Millam
J R
JR
Department of Avian Sciences, University of California, Davis 95616.
Faris
P L
PL
Youngren
O M
OM
el Halawani
M E
ME
Hartman
B K
BK
D000818:Animals; D000918:Antibody Specificity; D001923:Brain Chemistry / Q000502:physiology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000032:analysis; D007106:Immune Sera; D007150:Immunohistochemistry; D009412:Nerve Fibers / Q000737:chemistry; D009474:Neurons / Q000737:chemistry; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D014422:Turkeys / Q000378:metabolism*
D007106:Immune Sera; D007987:Gonadotropin-Releasing Hormone; C037700:LHRH, Gln(8)-; C047717:LHRH, His(5)-Trp(7)-Tyr(8)-; D011761:Pyrrolidonecarboxylic Acid