title: Hypothalamic estrogen receptor-immunoreactivity in prepubertal vs adult female guinea pigs.
abstract: Juvenile guinea pigs (18-20 days old) rarely display lordosis in response to estradiol and progesterone treatments that elicit sexual behavior in adult females. Nor do immature animals release a preovulatory-like surge of luteinizing hormone in response to estradiol. In vitro radioligand binding assays have revealed similar concentrations of estrogen receptors in the hypothalamus and preoptic area of prepubertal and adult guinea pigs. The aim of the present study was to compare estrogen receptor-immunoreactivity in a variety of forebrain regions of immature and adult guinea pigs, to determine whether age differences in estrogen receptor levels in more discrete portions of the hypothalamus and preoptic area exist. Forebrain tissue from juvenile (17 days) and adult females (> 6 weeks), ovariectomized 6 days previously, was processed for estrogen receptor-immunoreactivity, using Abbott Laboratories' H222 anti-human estrogen receptor antibody. Juveniles had estrogen receptor-immunoreactive cells in all of the same regions as adults: medial preoptic area, medial preoptic nucleus, bed nucleus of the stria terminalis, periventricular, paraventricular, dorsomedial and arcuate nuclei, ventrolateral and anterior hypothalamic regions, and amygdala. Among the areas in which estrogen receptor-immunoreactivity was quantified (medial preoptic area, medial preoptic nucleus, anterior periventricular nucleus, arcuate nucleus and ventrolateral hypothalamus), the only region in which an age difference in estrogen receptor-immunostaining was observed was the rostral portion of the ventrolateral hypothalamus. Juvenile females had, on average, 30% fewer estrogen receptor-immunoreactive cells in a sample of this region than adults (440 +/- 25 vs. 626 +/- 25, P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Psychology Department, University of California, Santa Barbara 93106.
authors.forename: D H
authors.initials: DH
authors.lastname: Olster
mesh_terms: D000375:Aging; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000737:chemistry; D005260:Female; D006168:Guinea Pigs; D007031:Hypothalamus / Q000737:chemistry / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000737:chemistry; D011301:Preoptic Area / Q000737:chemistry; D011960:Receptors, Estrogen / Q000032:analysis / Q000378:metabolism*; D012741:Sexual Maturation; D014018:Tissue Distribution
chemical_list: D011960:Receptors, Estrogen