title: The influence of 17beta-estradiol on annexin 1 expression in the anterior pituitary of the female rat and in a folliculo-stellate cell line.
abstract: Annexin 1 (ANXA1) is a Ca2+- and phospholipid-binding protein that plays an important role as a mediator of glucocorticoid action in the host-defence and neuroendocrine systems. Sex differences in hypothalamo-pituitary-adrenal (HPA) axis activity are well documented and a number of studies have demonstrated that gonadal steroids act as regulators of HPA activity. The aim of this study was to investigate the effect of ovariectomy and 17beta-estradiol replacement, and estrous cycle stage, on anterior pituitary ANXA1 content. The amount of anterior pituitary ANXA1 determined by western blotting varied with estrous cycle stage with a peak at estrus declining to a trough at proestrus. Ovariectomy resulted in a significant (P<0 x 05) decrease in anterior pituitary ANXA1 content. Administration of 17beta-estradiol (1 microg/100 g) significantly (P<0 x 01) increased anterior pituitary ANXA1 expression in the ovariectomized animals. In contrast, there was no change in pituitary ANXA1 content in response to 17beta-estradiol in adrenalectomized and adrenalectomized/ovariectomized rats. Treatment of TtT/GF cells, a folliculo-stellate cell line, with 17beta-estradiol (1 x 8-180 nM) increased ANXA1 mRNA expression and increased the amount of ANXA1 protein externalized in response to a dexamethasone stimulus. These results indicate that 17beta-estradiol stimulates ANXA1 expression in the anterior pituitary and in vivo an adrenal factor contributes to the mechanism of action.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Davies
authors.forename: Selma
authors.initials: S
authors.lastname: Omer
authors.forename: John F
authors.initials: JF
authors.lastname: Morris
authors.forename: Helen C
authors.initials: HC
authors.lastname: Christian
mesh_terms: D000315:Adrenalectomy; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D017305:Annexin A1 / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D003345:Corticosterone / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004958:Estradiol / Q000494:pharmacology*; D030762:Estrous Cycle; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism; D010052:Ovariectomy; D010903:Pituitary Gland, Anterior / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013268:Stimulation, Chemical
chemical_list: D017305:Annexin A1; D005938:Glucocorticoids; D012333:RNA, Messenger; D004958:Estradiol; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone