Estrogen concentration by substance P-immunoreactive neurons in the medial basal hypothalamus of the female rat.
We used the combined technique of steroid autoradiography and immunohistochemistry to simultaneously visualize estrogen-concentrating and substance P-immunoreactive (sP-IR) cells. A substantial proportion (26.1%) of sP-IR cells that bound estrogen was found in the anterior two thirds of the arcuate nucleus with a rapidly diminishing number of cases (8.7%) in the posterior extent of this nucleus. Highest proportions (42.9%) of sP-IR cells retaining estrogen were found in the ventrolateral part of the ventromedial hypothalamic nucleus. The ventral premammillary nucleus was observed to have both populations but coexistence was comparatively infrequent (2.4%). Occasional cases of coexistence were also found in the lateral hypothalamic area. These results provide anatomical evidence that a subset of sP-IR neurons are directly regulated by estrogen and support the hypothesis that sP-containing cells participate in the transduction of hormonal information into a CNS circuitry that regulates gonadotropin secretion and sexual behavior.
Akesson
T R
TR
Department of Anatomy, UCLA School of Medicine.
Micevych
P E
PE
D000818:Animals; D001345:Autoradiography; D002452:Cell Count; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D007033:Hypothalamus, Middle / Q000378:metabolism*; D007150:Immunohistochemistry; D010052:Ovariectomy; D051381:Rats; D013373:Substance P / Q000378:metabolism*
D013373:Substance P; D004958:Estradiol