Endocrine Abstracts

Recent advances in tridimensional (3D) tissue imaging and development of reporter proteins have provided new insight into the dynamic relationship between tissue structure, function and dysfunction in a number of fields of research. In developmental biology 3D microscopy has enabled building of quantitative 3D atlases of embryo morphology and gene expression at cellular resolution and in neuroscience ‘connectomics’, the building of 3D brain connectivity maps is a rap...

Glucocorticoids act within the pituitary gland to maintain the blood levels of glucocorticoids within appropriate limits by negative feedback on the secretion of corticotrophin (ACTH). Annexin 1 (ANXA1) is a calcium- and phospholipid binding protein which was originally identified as a mediator of the anti-inflammatory actions of glucocorticoids in the host defence system. Subsequent work has shown that it that plays an important role in the early delayed (30 min-3 h) feedback...

Introduction: The N-formyl peptide receptor (FPR) family of G-protein-coupled receptors, originally identified to recognise N-formylated bacterial peptides, has in more recent times been shown to bind annexin-1 (ANXA1). ANXA1 is a signalling molecule well demonstrated to mediate two key glucocorticoid effects in the anterior pituitary: inhibition of ACTH release from corticotrophs and regulation of cell proliferation. Whilst previous RT-PCR studies have detec...

Calcium mobilization from intracellular stores represents an important cell signalling process that is regulated, in mammalian cells, by inositol-1,4,5-triphosphate (IP3), cyclic ADP ribose (cADPR) and nicotinic acid adenine dinucleotide phosphate (NAADP). Intracellular calcium is important for mobilization of secretory granules to the plasma membrane in preparation for exocytosis. NAADP mobilizes calcium from lysosome-related acidic compartments and it has been sho...

Folliculostellate (FS) cells constitute around 10% of the adenohypophyseal cell population. Various functions of these non-endocrine cells have been elucidated, including the paracrine control of the function of local endocrine cells. FS cell development is currently very poorly understood. In this study FS cell appearance during embryonic chick development between pre-natal stages (st)17-37 was examined. Gene and protein expression of the FS marker proteins annexin A1 (AnxA1)...

The sonic hedgehog (shh) pathway is known to be essential for pituitary development but little is known of its role in adult pituitary. Patched1, encoded by the Patched1 (Ptch1) gene, is a receptor for shh expressed in all cell types of the anterior pituitary. Adult onset hypogonadotropic hypogonadism has been reported in a genetically engineered mouse line with deletion of Ptch1 using S100a4 promoter driven CRE recombinase expression which is restri...

Folliculo-stellate (FS) cells exert a paracrine regulation on their neighbouring endocrine cells in the anterior pituitary gland. FS cells are non-granular cells characterized by long cytoplasmic processes and form follicles with microvilli on their luminal cavity, suggesting a transport function. Moreover, FS cells form monolayers in primary culture and develop domes after reaching confluence, characteristics of polarized transport epithelia. However little is known about tra...

Recent studies have demonstrated that rather than being a collection of heterogeneously dispersed cells, the pituitary gland is wired by multiple and specific endocrine cell networks to synchronise hormone release. Prolactin (PRL) is primarily important for lactation. In response to changing physiological demands during pregnancy and lactation the pituitary has the ability to expand and contract its cell number. We have investigated changes in lactotroph morphology and cell-to...

Annexin 1 (ANXA1) was first identified as a glucocorticoid (GC)-inducible protein in macrophages and is a mediator of the powerful anti-inflammatory actions of these steroid hormones. In the pituitary ANXA1 plays a critical role in mediating the early-onset negative feedback effects of GCs on the release of ACTH. ANXA1 is expressed in abundance in the anterior pituitary gland where it is localized specifically to the S100-positive folliculo-stellate (FS) cells. GCs act on FS c...

Annexin 1 (ANXA1) externalised from folliculostellate cells is known to be an essential intermediate in the early delayed (30 min- 3 h) negative feedback of glucocorticoids on the release of ACTH and other pituitary hormones. We have used a well-characterised folliculostellate cell line (TtT/GF cells) to investigate the mechanism by which ANXA1, a cytoplasmic protein, is externalised by cells. Externalisation is stimulated by dexamethasone (Dex) and inhibited by inhibitors of ...