Endocrine Abstracts

Annexin 1 (ANXA1) is a member of the annexin family of phospholipid- and calcium- binding proteins with a well-demonstrated role in the inhibitory actions of glucocorticoids on the release of ACTH, TSH, GH and PRL from the anterior pituitary. ANXA1 and ANXA1 truncated peptides have also recently been found to mimic glucocorticoid suppression of LH release (John et al, 2003 J Neuroendocrinol 15, 946-57). Here we test the hypothesis that because ANXA1 mediates some of the inhibi...

Annexin 1 (ANXA1) is a Ca 2+ and phospholipid binding protein that plays an important role as a mediator of glucocorticoid (GC) action in the host-defence and neuroendocrine-systems. Our previous studies (Christian et al., 1998) in ovarietomised rats +/- oestradiol (E2) replacement suggested oestrogen may exert an inhibitory influence on ANXA1 expression in the pituitary gland. Our more recent finding that ANXA1 knockout mice exhibit unexpected sexual dimorphisms in...

Annexin 1 (ANXA1) plays an essential role in the 'early-delayed' feedback effects of glucocorticoids (GCs) on ACTH release. Evidence that ANXA1 is externalised from pituitary cells in response to GCs, together with the finding that the protein is localised mainly to the folliculo-stellate (FS) cells, has led us to propose that ANXA1 is a paracrine mediator of GC action in the anterior pituitary. To address this hypothesis we have examined ANXA1-dependent GC actions in co-cultu...

Annexin I (ANXA1), a Ca2+- and phospholipid-binding protein is an important mediator of glucocorticoid (GC) action in the host defence and neuroendocrine systems. In the anterior pituitary ANXA1 is highly expressed by the folliculo-stellate (FS) cells (1). We have shown that GCs cause the externalization of annexin I in a FS cell line (murine TtT/GF) despite the fact that ANXA1 lacks a signal sequence and is not packaged in secretory granules. In bacteria and yeast ...

The secretion of prolactin is sexually dimorphic and sensitive to changes in gonadal steroid and glucocorticoid status. Reports that the regulatory effects of glucocorticoids on prolactin release are mediated in part via annexin I (ANXA1, 1), have led us to compare prolactin secretion in ANXA1 knockout (KO) and wildtype (WT) mice and to determine the effects ovariectomy and oestrogen replacement (80 nanograms/0.1 ml, s.c./day) on (a) the plasma prolactin concentration (radioim...

Annexin 1 (ANXA1, lipocortin 1), a Ca2+ and phospholipid binding protein, is a strong candidate mediator of the interplay between the immune and neuroendocrine systems. Within the neuroendocrine system ANXA1 is expressed in abundance by the non-secretory pituitary folliculo-stellate (FS) cells (1), which show characteristics of resident microglia. We have previously reported that IL-6 up-regulates ANXA1 expression in the liver in vivo and in A549 cells (lung epithelial...

Annexin-1 (Anx-1), a 37 kDa protein, is a member of the super-family of Ca2+and phospholipid-binding annexin proteins and acts as a mediator of glucocorticoid (GC) action in the host defence and neuroendocrine systems. In the anterior pituitary Anx-1 is expressed mainly by folliculostellate (FS) cells and mediates the early-delayed feedback inhibition exerted by GCs on the release of ACTH and other pituitary hormones.The stress responsiveness ...

Acknowledgements: This work was generously supported by the Wellcome TrustAnnexin 1 (ANXA1) plays an important role in mediating the negative feedback effects of glucocorticoids on the HPA axis. It is released from non-secretory folliculostellate (FS) cells by glucocorticoids and acts locally to suppress ACTH release from corticotrophs. Previous studies suggest that the steroid-induced translocation of ANXA1 across the FS cell membrane is effected via me...

Annexin 1 (ANXA1) plays an important role in mediating the negative feedback effects of glucocorticoids on the HPA axis. In the anterior pituitary gland ANXA1 is localised mainly to the non-secretory folliculostellate (FS) cells. It is released from these cells by glucocorticoids and acts locally to suppress ACTH release from corticotrophs. Functional and histological studies suggest that the steroid-induced translocation of ANXA1 across the FS cell membrane is effected via me...

The anti-inflammatory actions of glucocorticoids are mediated in part by inhibition of nuclear factor kappa B (NFkappaB) activation. Reports that NFkappaB activation within anterior pituitary folliculo-stellate (FS) cells provokes the release of interleukin-6 (IL-6) [1] which acts a paracrine mediator of ACTH release [2], raise the possibility that NFkappaB is a potential target for the negative feedback actions of glucocorticoids upon the hypothalamo-pitu...