Endocrine Abstracts

The effects in vitro and in vivo of somatostatin (SS) analogues are linked to the presence of specific binding sites on target cells. Estradiol (E2) may modulate the expression of SS receptors (SSTR) in some cell models, including breast cancer and pituitary cells. Aim of this study was to evaluate the effects of E2 on SSTR1-5 ligand binding domains (LBD) expression levels in prostate epithelial cells (PEC).Methods: We investigated the effe...

Liver X receptors (LXRalfa and LXRalfa) act on the cholesterol homeostasis in several tissues, including adrenals. In particular, LXRalfa regulates the expression of several genes involved in the cholesterol efflux and storage and modulates glucocorticoid synthesis in mice. The level of the expression of LXRs in the human adrenal adenomas is unknown. We evaluated LXRalfa and LXRbeta mRNA levels in cortisol-secreting adenomas (CSA) and in the surrounding normal tissue, obtained...

The stable somatostatin analog octreotide has been successfully used for imaging and treatment of a variety of human tumors. Octreotide treatment has been reported of limited value in pheochromocytoma (PHEO). PHEOs often express more than one somatostatin receptor, and it is uncertain by which receptor subtype the functional responses of octreotide are mediated. A recent study showed by immunohistochemical staining that vast majority of tumors (90%) were positive for sst(3), i...

Recently it has been shown that somatostatin (SST) might be of therapeutic value in the treatment of active Graves’ophthalmopathy (GO). SST and somatostatin receptors (sst) transcripts are expressed and functional in cultured orbital fibroblasts deriving from GO patients (FGO). Octreotide, the SST analogue currently used is able to inhibit in vitro growth and activity of FGO. New analogues with wider sst-affinity are now available for in vitro experim...

Pasireotide (SOM230), a somatostatin (SST) analogue targeting multiple SST receptors, is effective in reducing urinary free cortisol in patients with Cushing disease (CD), due to inoperable or recurrent ACTH secreting pituitary adenomas. The efficacy of SOM230 seems to be dependent on the presence of appropriate SSTRs, mainly SSTR2 and 5, on the membrane of tumor cells. Polyclonal antibodies available up to now recognizing cellular intracellular sites of receptors and their re...

Classical somatostatin analogues (SST-A), such as octreotide and lanreotide, bind mainly SSTR2 whilst the multiligand pasireotide binds with the highest affinity SSTR5. The selective immunodetection of ligand binding domain (LBD) of SSTR subtypes with specific monoclonal antibodies may be useful to explain the potential efficacy of different SSTA on pituitary tumours growth and/or secretory activity.Patients and Methods: We applied new monoclonal antibod...