Endocrine Abstracts

Annexin 1 (Anx-1), a 37kDa protein, is a member of the super-family of Ca 2+ and phospholipid-binding annexin proteins and acts as a mediator of glucocorticoid (GC) action in the host defense 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. It has been previously demonstrated that TtT/GF...

Colocalisation of hormones has been demonstrated for growth hormone (GH) and prolactin in the normal adult human pituitary, and for many other hormones in pituitary adenomas. We have investigated whether colocalisation of GH and other hormones occurs earlier, during onto-genesis. Pituitaries from therapeutically aborted male human fetuses of 15–20 weeks gestational age (with ethical approval) were fixed by immersion in 4% buffered formaldehyde and divided in halves, one o...

Annexin A1 (AnxA1) acts as a mediator of glucocorticoid (GC) actions in 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 release of ACTH and other pituitary hormones. GC cause the externalization of AnxA1. The stress responsiveness of the female rat hypothalamo-pituitary-adrenal system varies with the estrous cycle, with increased CORT release in resp...

Colocalisation of hormones in the adult human pituitary has been demonstrated only for growth hormone (GH) and prolactin (PL) and only for adenomatous tissue. We have investigated whether colocalization occurs earlier in ontogenesis. Pituitaries from male human fetuses of 16–22 weeks gestational age fixed by immersion in 4% buffered formaldehyde and embedded in LR Gold were processed for immunocytochemical double labelling with GH/FSH or GH/LH anti-rat and anti-human prim...

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. Consistent with these findings plasma PRL content is raised in male ANXA1 null mice vs wild-type controls (Cover et al Endocrine Abstracts 8, P69). Here we test the hypothesis that because ANXA1 mediates some of the inhibitory actions of ...

VEGF (vascular endothelial growth factor) is an endothelial cell mitogen responsible for physiological and pathophysiological angiogenesis. Abnormal regulation of VEGF expression in anterior pituitary folliculostellate (FS) cells has been implicated in pituitary tumour progression. PACAP is a well-documented stimulant of VEGF secretion from the pituitary in which both FS and endocrine cells express VEGF. TtT/GF cells are a mouse pituitary cell line with many characteristics of...

Prolactin secretion 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 1 (ANXA1, 1), have led us to compare prolactin secretion and lactotroph morphology in ANXA1 knockout (KO) and wildtype (WT) mice and to determine the effects gonadectomy +/- testosterone replacement (80 micrograms per day, s.c.) on (a) the plasma prolactin co...