The influence of 17 -estradiol on annexin 1 expression in the anterior pituitary of the female rat and in a folliculo-stellate cell line

Davies, E., Omer, S., Morris, J.F. and Christian, H.C. (2007) The influence of 17 -estradiol on annexin 1 expression in the anterior pituitary of the female rat and in a folliculo-stellate cell line. Journal of Endocrinology, 192 (2), 429-442. (doi:10.1677/JOE-06-0132). (PMID:17283243)

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 ovariectomyand 17?-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<0.05) decrease in anterior pituitary ANXA1 content. Administration of 17?-estradiol (1 ?g/100 g) significantly (P<0.01) increased anterior pituitary ANXA1 expression in the ovariectomized animals. In contrast, there was no change in pituitary ANXA1 content in response to 17?-estradiol in adrenalectomized and adrenalectomized/ovariectomized rats. Treatment of TtT/GF cells, a folliculo-stellate cell line, with 17?-estradiol (1.8–180 nM) increased ANXA1 mRNA expression and increased the amount of ANXA1 protein externalized in response to a dexamethasone stimulus. These results indicate that 17?-estradiol stimulates ANXA1 expression in the anterior pituitary and in vivo an adrenal factor contributes to the mechanism of action.

This record has no associated files available for download.

Contributors

Download statistics