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Titolo:
Effects of chronic oestrogen replacement on stress-induced activation of hypothalamic-pituitary-adrenal axis control pathways
Autore:
Dayas, CV; Xu, Y; Buller, KM; Day, TA;
Indirizzi:
Univ Queensland, Dept Physiol & Pharmacol, Brisbane, Qld 4072, Australia Univ Queensland Brisbane Qld Australia 4072 Brisbane, Qld 4072, Australia
Titolo Testata:
JOURNAL OF NEUROENDOCRINOLOGY
fascicolo: 8, volume: 12, anno: 2000,
pagine: 784 - 794
SICI:
0953-8194(200008)12:8<784:EOCORO>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEDULLA CATECHOLAMINE CELLS; MESSENGER-RIBONUCLEIC-ACID; ESTROGEN-RECEPTOR-ALPHA; PARAVENTRICULAR NUCLEUS; POSTMENOPAUSAL WOMEN; RAT HYPOTHALAMUS; FEMALE RAT; C-FOS; SYSTEMIC INTERLEUKIN-1-BETA; NEUROENDOCRINE RESPONSES;
Keywords:
immune challenge; noise; oxytocin; amygdala; catecholamine cells;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
51
Recensione:
Indirizzi per estratti:
Indirizzo: Dayas, CV Univ Queensland, Dept Physiol & Pharmacol, Brisbane, Qld 4072, Australia Univ Queensland Brisbane Qld Australia 4072 Qld 4072, Australia
Citazione:
C.V. Dayas et al., "Effects of chronic oestrogen replacement on stress-induced activation of hypothalamic-pituitary-adrenal axis control pathways", J NEUROENDO, 12(8), 2000, pp. 784-794

Abstract

Oestrogen replacement therapy reportedly suppresses hypothalamic-pituitary-adrenal (HPA) axis responses to an emotional stressor in postmenopausal women. However, most studies in the rat suggest a facilitatory role for oestrogen in the control of HPA axis function. One explanation for this difference may be the regimen of oestrogen replacement: during oestrogen replacement therapy, oestrogen levels are low and constant whereas most animal studies examined the HPA axis response when oestrogen levels are rising. In the present study, we assessed HPA axis stress responses in mature ovariectomized rats after plasma oestrogen levels had been maintained at physiological levels for a prolonged period (25 or 100 pg/ml for 7 days). In the case of both an emotional stressor (noise) and a physical stressor (immune challengeby systemic interleukin-1 beta administration), oestrogen replacement suppressed stress-related Fos-like immunolabelling, in hypothalamic neuroendocrine cells and plasma adrenocorticotropin hormone responses. From the present data, and past reports, it appears unlikely that these effects of oestrogen are due to a direct action on corticotropin-releasing factor or oxytocincells. Therefore, to obtain some indication of oestrogen's possible site(s) of action, Fos-like immunolabelling was mapped in the amygdala and in brainstem catecholamine groups, which are neuronal populations demonstrating substantial evidence of involvement in the generation of HPA axis stress responses. In the amygdala, oestrogen replacement suppressed central nucleus responses to immune challenge, but not to noise. Amongst catecholamine cells, oestrogen replacement was more effective against responses to noise than immune challenge, suppressing A1 and A2 (noradrenergic) and C2 (adrenergic)responses to noise, but only A1 responses to immune challenge. These data suggest that, as in postmenopausal women on oestrogen replacement therapy, chronic low-level oestrogen replacement can suppress HPA axis stress responses in the rat. Moreover, oestrogen appears to exert effects at multiple sites within putative HPA axis control pathways, even though most of the relevant neuronal populations do not contain genomic receptors for this gonadalsteroid and the pattern of oestrogen action differs for an emotional vs a physical stressor.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/11/20 alle ore 06:00:51