Induction of Fos in the accessory olfactory system by male odors persists in female mice with a null mutation of the aromatase (cyp19) gene.
The ability of odors from soiled male bedding to induce neuronal Fos-immunoreactivity (IR) in sensory neurons located in both the apical and basal zones of the vomeronasal organ (VNO) and in two segments of the VNO-projection pathway, the anterior nucleus of the medial amygdala and the bed nucleus of the stria terminalis (BNST), was significantly reduced in adult, ovariectomized, estrogen-treated female mice with a homozygous null mutation of the cyp19 gene (ArKO) which encodes the estrogen biosynthetic P450 enzyme, aromatase. However, a significant odor-induced activation of Fos-IR was seen in other segments of the VNO-projection pathway of ArKO females, including the accessory olfactory bulb (AOB) granule cell layer, the posterior-dorsal medial amygdala (MePD), and the medial preoptic area (MPA). These results suggest that the VNO/accessory olfactory pathway to the hypothalamus was functional in ArKO females even though they had presumably been exposed to less estrogenic stimulation than wild-type (WT) control females throughout development and until the time that estrogen treatment was begun in adulthood. Thus, the hypothesis of Toran-Allerand [Prog. Brain Res. 61 (1984) 63] that female-typical features of neuroendocrine and behavioral function require perinatal exposure to estrogen was not supported, at least for the VNO/accessory olfactory system.
Lau
Y E
YE
Department of Biology, Boston University, Cummington St., Boston, MA 02215, USA.
Cherry
J A
JA
Baum
M J
MJ
Mani
S K
SK
D000818:Animals; D001141:Aromatase / Q000235:genetics*; D001512:Bedding and Linens; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D009812:Odorants; D009830:Olfactory Bulb / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010052:Ovariectomy / Q000379:methods; D010675:Pheromones / Q000494:pharmacology*; D011301:Preoptic Area / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D012737:Sex Factors; D013268:Stimulation, Chemical; D019147:Vomeronasal Organ / Q000187:drug effects / Q000378:metabolism
D010675:Pheromones; D016760:Proto-Oncogene Proteins c-fos; C074283:estradiol 3-benzoate; D004958:Estradiol; D001141:Aromatase