title: Induction of substance P-immunoreactivity by estrogen in neurons containing estrogen receptors in the anterovental periventricular nucleus of female but not male rats.
abstract: Effects of gonadal steroids on numbers of neurons containing estrogen receptor (ER) and/or substance P (SP) were examined in the anteroventral periventricular nucleus (AVPV) of female and male rats by double-labeling immunohistochemistry employing antibodies specific for ER and SP. Animals were gonadectomized and received subcutaneously either oil alone (Control group), sequential injections of estradiol benzoate and oil (EB + Oil group), or those of EB and progesterone (EB + P group). In the female control rat, a large population of ER-immunoreactive (IR) cells were found clustered throughout the AVPV. They were counted more than 2,000 in total of 4 sections in this nucleus. On the contrary, SP-IR neurons were scarcely observed in the same area of this group. Administration of estrogen to female animals decreased the total number of ER-IR cells to 67% of the control group. In contrast to the supressive effect of estrogen to its own receptor, it induced SP-IR neurons in the AVPV of the female. Approximately 50-80 SP-IR neurons were counted in the 4 sections, and 59% of these neurons expressed ER-IR material in their nuclei. In the female EB + P group, the number of ER-IR neurons also decreased to 79% of the control group. Although the number of SP-IR neurons in this group decreased to 32% of that in the EB + Oil group, a ratio of coexistence of ER-IR material in these neurons increased to 75%. The male control group contained a smaller population of ER-IR cells relative to the female control (1497 vs 2143).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anatomy and Embryology, Tokyo Metropolitan Institute for Neuroscience, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Okamura
authors.forename: M
authors.initials: M
authors.lastname: Yokosuka
authors.forename: S
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D002369:Castration; D002452:Cell Count; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000378:metabolism*; D012727:Sex Characteristics; D013373:Substance P / Q000096:biosynthesis*
chemical_list: D011960:Receptors, Estrogen; D013373:Substance P; D011374:Progesterone; D004958:Estradiol