Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four tumors consisting of pituitary adenomatous cells (AD) intricated with ganglion cells (GC) were studied. Each case was associated with a different clinical syndrome: acromegaly, amenorrhea-galactorrhea, Cushing's disease and isolated tumoral syndrome with no hormonal hypersecretion. (a) In the case with acromegaly, immunoreactive growth hormone (IR-GH) was present in 80% of AD. IR-vasoactive intestinal peptide (VIP) was found in 5%-10% of AD and in few GC. Rare GC and processes showed IR-GH-releasing hormone (GRH), -somatostatin (SRIH), -gonadotropin-releasing hormone and -adrenocorticotropin-releasing hormone. (b) In the case with amenorrhea-galactorrhea, IR-prolactin (PRL) was seen in 90% of AD. IR-PRL and -VIP were present in rare GC. (c) In the case with Cushing's disease, 60% of AD and very few GC contained IR-adrenocorticotropin (ACTH) and beta-lipotropin. Rare GC processes contained IR-SRIH. (d) In the case without pituitary hormone hypersecretion, PRL was localized in rare AD and GC. Pituitary hormone and neuropeptides were never colocalized in the same cells. No case displayed IR-neurophysins or -thyroliberin. Pituitary hormones were localized by ultrastructural immunogold labeling. These findings show that: (i) in three cases, pituitary hormones (PRL and ACTH), and, in one case, VIP could be localized in both adenomatous and ganglion cells; (ii) the pituitary hormone-containing cells in the tumors could be related to the hypersecretory syndromes; (iii) intratumoral IR-VIP and -GRH might be involved in GH and PRL hypersecretion in the cases with acromegaly and amenorrhea-galactorrhea.
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PMID:Immunocytochemistry of four mixed pituitary adenomas and intrasellar gangliocytomas associated with different clinical syndromes: acromegaly, amenorrhea-galactorrhea, Cushing's disease and isolated tumoral syndrome. 292 94

This paper reports the case of a 31-year-old woman with hyperthyroidism, increased TSH and thyroid hormone levels, evidence of a pituitary adenoma, hyperprolactinaemia, amenorrhoea, and galactorrhoea. Following trans-sphenoidal pituitary adenomectomy, mild hyperthyroidism and increased TSH and alpha subunit levels persisted, whereas hyperprolactinaemia, amenorrhoea, and galactorrhoea disappeared. Serum TSH levels were not affected by administration of TRH, metochlopramide, domperidone, l-dopa or somatostatin. Serum TSH chromatography showed a normal pattern. Following a second trans-sphenoidal pituitary adenomectomy and radiotherapy, hyperthyroidism disappeared, and the TSH and alpha subunit levels returned to normal. Light microscopy showed no specific TSH immunostaining although electron microscopy revealed numerous secretory granules alined along the plasma membrane. The post-operative follow-up confirmed the presence of a TSH-secreting pituitary adenoma associated to functional hyperprolactinaemia.
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PMID:Hyperthyroidism due to a thyroid-stimulating hormone (TSH)-secreting pituitary adenoma associated with functional hyperprolactinaemia. A case report. 342 60

Major advances in our understanding of the synthesis and release of anterior pituitary hormones have been made over the past several years. Neurons of the hypothalamus have been found to serve as "neuroendocrine transducers" in that they have both electrical and secretory functions. Peptidergic neurons respond to appropriate stimuli with a release of hypothalamic factors into the hypophyseal-portal system. These factors or hormones ultimately control the endocrine function of anterior pituitary cells. Three hormones, Thyrotropin Releasing Hormone (TRH), Gonadotropin Releasing Hormone (GnRH or LHRH) and somatostatin have been identified, synthesized and tested for clinical applications. The clinical assessment of pituitary function has been greatly improved by new and improved radioimmunoassays. One of the recent clinical advances in the area of pituitary disease has been the determination of the relatively high frequency of prolactinomas. Prolactin secreting microadenomas are an important and treatable cause of amenorrhea and infertility in young women. In addition, many pituitary tumors previously believed to be non-functional or "chromophobe adenomas" appear to be prolactinomas. Many new diagnostic and therapeutic techniques are continuing to be developed to improve our management of patients with hypothalamic-pituitary disease.
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PMID:Recent advances in the control and function of the anterior pituitary. 627 29

A 20-year-old female presented with thyrotoxicosis associated with amenorrhoea and galactorrhoea after oral contraceptive withdrawal. Serum TSH was persistently elevated (mean: 28 +/- 3.1 microU/ml during 24-h sampling and did not vary significantly after TRH, bromocriptine or somatostatin. Prolactin levels remained constantly at the upper limit of normal (mean: 20.6 +/- 2.1 ng/ml, with a minimal increase after TRH, a slight decrease after somatostatin (54%) and a marked decrease after bromocriptine (88.5%). Surgical exploration revealed an unusually firm tumour adherant to the wall of the sella turcia; electron microscopic study showed that it was composed almost exclusively of thyrotrophs. After a transient period of euthyroidism post-operatively, T3 toxicosis occurred with an increased TSH level (15.5 microU/ml) and a rise in TSH and alpha subunit in response to TRH. An increase in T4 followed while prolactin remained low.
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PMID:Hyperthyroidism due to a pituitary TSH secreting tumour with amenorrhoea-galactorrhoea. 718 98

Initially, the distinction between "functional" and "non-functional" adenomas was a purely clinical notion. A "non-secreting" adenoma was not considered to cause acromegaly nor Cushing's syndrome nor amenorrhea-galactorrhea syndrome. The term "chromophobe adenoma" has been used since the advent Herlant tetrachrome. More recently immunocytochemistry methods have demonstrated that most of the "clinically non functional" adenomas (chromophobe with classical histology) are actually gonadotrophin secreting adenomas or gonadotroph adenomas. Due to progress in immunocytochemistry applied to operated adenomas, it is now known that gonadotroph tumors account for 15 to 20% of all pituitary adenomas. Gonadotroph adenomas are monoclonal but their pathogenesis, unlike somatotroph adenomas causing acromegaly and despite numerous molecular studies, remains unknown. Gonadotroph adenomas are most always discovered in patients presenting a pituitary syndrome (half to three-quarters consult for a visual field disorder). Pituitary imaging almost always demonstrates a macroadenoma: two-thirds of the macroadenomas are enclosed. Anterior pituitary insufficiency is much more frequent than gonad hyperstimulation whether testicular (macro-orchidia) or ovarian (ovarian hyperstimulation similar to that observed in ovulation induction). A careful analysis of hormone assay results shows that baseline concentrations of gonadotrophin or their free sub-units is elevated in 30 to 50% of cases (especially FSH in men, and the free a sub-unit in premenopausal women). Dynamic tests contribute little to diagnosis: the GnRH test is positive in 75 to 100% of cases, the TRH test in 60 to 70% for FSH (or alpha) and when there is already a baseline hypersecretion of FSH (or a) in 20 to 30% of the cases for the LH when the baseline LH concentration is high. The immunocytochemistry of gonadotroph adenomas is slightly different from that of other adenomas: generally, only 5 to 10% of the cells, grouped in islets of variable size, dispersed in the tumoral parenchyma, bind anti-FH, anti-LH and/or anti-sub-unit a antisera. Surgery is the primary treatment for gonadotroph adenomas. Complementary radiotherapy may be discussed in case of a postoperative remnant. It is probably effective against recurrence. Medical treatment (dopaminergic agonists, somatostatin analogs, GnRH agonists and antagonists) have given disappointing results.
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PMID:[Gonadotroph pituitary adenomas]. 1097 Sep 52

Thyrotropin (TSH)-secreting adenomas are rare and, as most adenomas are large, invasive and difficult to cure by surgery only, many require additional medical treatment. Many TSH-secreting adenomas cosecrete growth hormone (GH) and/or prolactin (PRL). We evaluated the relationship between pathology and the effect of dopamine agonist bromocriptine and somatostatin analogue octreotide in 20 operated patients with TSH-secreting adenomas. The four men and 16 women ranged in age from 23 to 62 years; three had clinically overt acromegaly; two manifested galactorrhea-amenorrhea. Endocrinologically, elevated serum GH, and/or IGF-1 were observed in six patients and elevated serum PRL was observed in eight. Immunohistochemically, 16 of the 20 adenomas were positive for GH and/or PRL (GH-positive, n=13; PRL-positive, n=9). Pituitary-specific transcription factor Pit-1 was demonstrated in the nuclei of all adenoma cells. Octreotide tests showed suppression of serum TSH (<50%) in ten of 14 patients. Preoperative octreotide treatment effectively reduced serum TSH and tumor size in two patients. Electron micrographs of octreotide-treated TSH-secreting adenomas showed shrinkage of the cytoplasm and diffuse distribution of secretory granules. Our study suggests that cosecretion of GH and/or PRL from TSH-secreting adenoma has no correlation with response of tumor cells to medical treatment.
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PMID:Pathological study of thyrotropin-secreting pituitary adenoma: plurihormonality and medical treatment. 1518 2

Regardless of etiology, all cases of endogenous Cushing's syndrome are due to increased production of cortisol by the adrenal gland. Most are caused by adrenocorticotrophic hormone (ACTH)-secreting pituitary adenomas. Alternatively, the glucocorticoid excess may be due to adrenal neoplasia or to ectopic ACTH-secreting tumors. Cushing's syndrome is characterized by endocrine and metabolic alterations such as truncal obesity, hypertension, weakness, amenorrhea, hyperglycemia, osteoporosis and depression. Unless treated, the disease is associated with high morbidity, and ultimately, mortality. Depending on the etiology of Cushing's syndrome two different treatment modalities are possible: reduction of pituitary ACTH production or reduction of adrenocortical cortisol secretion. In the absence of efficient drug therapy, transsphenoidal resection of the pituitary adenoma is the primary treatment of choice for the reduction of ACTH secretion. In the last years there was much progress in understanding the molecular mechanisms that control the function of the hypothalamic-pituitary-adrenal axis. Thus, new insights made it possible to identify potential drug targets for the treatment of Cushing's syndrome. The present article reviews different drug targets and therapeutic options including drugs that control the central ACTH regulation, e.g. by modulating signaling pathways and transcriptional regulation of ACTH biosynthesis, corticotrophin releasing hormone (CRH) or glucocorticoid receptor antagonists, inhibitors of glucocorticoid synthesis, ketoconazole, somatostatin and dopamine analogs. Some of these substances might be useful for the treatment of Cushing's syndrome.
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PMID:New perspectives in the treatment of Cushing's syndrome. 1557 85

Pituitary tumors cause symptoms by secreting hormones (prolactin, PRL, responsible for amenorrhea-galactorrhea in women and decreased libido in men; growth hormone, GH, responsible for acromegaly; adrenocorticotropic hormone, ACTH, responsible for Cushing's syndrome; thyroid-stimulating hormone, TSH, responsible for hyperthyroidism), depressing the secretion of hormones (hypopituitarism), or by mass-related effects (headaches, visual field abnormalities...). All patients with pituitary tumors should be evaluated for gonadal, thyroid and adrenal function as well as PRL and GH secretion. Specific stimulation and suppression tests for pituitary hormones are performed in selected situations for detecting the type of hypersecretion or the response to treatment. Imaging procedures (mainly magnetic resonance imaging, MRI, nowadays) determine the presence, size and extent of the lesion. The classification of pituitary tumors is based on the staining properties of the cell cytoplasm viewed by light microscopy and immunocytochemistry revealing the secretory pattern of the adenoma. Treatment of pituitary adenomas consists of surgery (performed in more than 99% of cases via a transphenoidal route) and radiotherapy, generally fractionated or, in selected cases, using stereotactic techniques such as gamma-knife. The availability of medical treatment (dopamine, DA, agonists, somatostatin analogs, GH-receptor antagonists...) has profoundly modified the indications of radiotherapy, drugs being now generally used as a second-line treatment, after surgery (or even as first-line treatment). Based on the results of the different treatment modalities for each type of pituitary adenoma, recommendations will be proposed. They may be summarized as follows. For treatment of GH-secreting adenomas, trans-sphenoidal surgery is the first-line therapy except when the macroadenoma is giant or if surgery is contra-indicated; postoperative radiation therapy (fractionated, or by gamma-knife) is performed for partially resected tumors or when GH levels remain elevated (eventually after a trial of somatostatin analog). Somatostatin analogs, now available in slow release form, are proposed when surgery is contra-indicated, or has failed to normalize GH levels, or in waiting for the delayed effects of radiation therapy. If the probability of surgical cure is low (e.g. in patients with very large and/or invasive tumors), then somatostatin analogs may be reasonable primary therapeutic modality provided that the tumor does not threaten vision or neurological function. Pegvisomant, the new GH-receptor antagonist, is indicated in case of resistance to somatostatin analogs. Patients with PRL-secreting microadenomas may be treated either with trans-sphenoidal surgery or medically with DA agonists. In patients with macroadenomas, even in the presence of chiasmatic syndrome, DA agonists are now proposed as primary treatment. Indeed, effects on visual disturbances are often very rapid (within a few hours or days) and tumoral shrinkage is usually very significant. For patients with ACTH-secreting adenomas, primary therapy is generally trans-sphenoidal surgery by a skilled surgeon, whether or not a microadenoma is visible on MRI. Radiotherapy is reserved for patients who are subtotally resected or remain hyper-secretory after surgery. In waiting for the effects of radiotherapy, adrenal steroidogenesis inhibitors (mitotane, ketoconazole) may be indicated. If drugs are not available or not tolerated, bilateral adrenalectomy may be proposed. For patients with clinically non functioning adenomas (generally gonadotropin-secreting adenomas on immunocytochemistry), trans-sphenoidal surgery with or without postoperative radiation therapy is performed for almost all patients whether or not they have visual consequences of their tumor. Selected patients with small, incidentally discovered microadenomas may be carefully followed without immediate therapy.
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PMID:Diagnosis and treatment of pituitary adenomas. 1576 32

We describe a hitherto undocumented variant of dimorphic pituitary neoplasm composed of an admixture of neurosecretory cells and profuse leiomyomatous stroma around intratumoral vessels. Radiologically perceived as a macroadenoma of 3.8 cm in diameter, this pituitary mass developed in an otherwise healthy 43-year-old female. At the term of a yearlong history of amenorrhea and progressive bitemporal visual loss, subtotal resection was performed via transsphenoidal microsurgery. Discounting mild hyperprolactinemia, there was no evidence of excess hormone production. Histologically, solid sheets, nests and cords of epithelial-looking, yet cytokeratin-negative cells were seen growing in a richly vascularized stroma of spindle cells. While strong immunoreactivity for NCAM, Synaptophysin and Chromogranin-A was detected in the former, the latter showed both morphological and immunophenotypic hallmarks of smooth muscle, being positive for vimentin, muscle actin and smooth muscle actin. Architectural patterns varied from monomorphous stroma-dominant zones through biphasic neuroendocrine-leiomyomatous areas, to pseudopapillary fronds along vascular cores. Only endothelia were labeled with CD34. Staining for S100 protein and GFAP, characteristics of sustentacular cells, as well as bcl-2 and c-kit was absent. Except for alpha-subunit, anterior pituitary hormones tested negative in tumor cells, as did a panel of peripheral endocrine markers, including serotonin, somatostatin, calcitonin, parathormone and vasoactive intestinal polypeptide. Mitotic activity was absent and the MIB-1 labeling index low (1-2%). While assignment of this lesion to any established neoplastic entity is not forthcoming, we propose it is being considered as a low-grade neuroendocrine tumor possibly related to null cell adenoma.
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PMID:Leiomyomatoid angiomatous neuroendocrine tumor (LANT) of the pituitary: a distinctive biphasic neoplasm with primitive secretory phenotype and smooth muscle-rich stroma. 1652 Sep 66

Patients with anorexia nervosa (AN) may develop multiple endocrine abnormalities, including amenorrhea, hyperactivity of the hypothalamus-pituitary-adrenal axis, hypothyroidism and particular changes in the activity of the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis. Exaggerated GH secretion and reduced IGF-I levels are usually found in AN, as well as in conditions of malnutrition and malabsorption, insulin-dependent diabetes mellitus, liver cirrhosis and catabolic states. In AN, GH hypersecretion at least partially reflects malnutrition-induced peripheral GH resistance, which leads to reduced IGF-I synthesis and release; this implies an impairment of the negative IGF-I feedback action on GH secretion. On the other hand, primary alterations in the neural control of GH secretion cannot be ruled out. The neuroendocrine alterations include enhanced somatotroph responsiveness to growth hormone releasing hormone (GHRH) and impaired GH response to most central nervous system-mediated stimuli. Particular resistance to cholinergic manipulation has also been demonstrated, thus suggesting a somewhat specific alteration in the somatostatin (SS)-mediated cholinergic influence on GH secretion. Moreover, paradoxical GH responses to glucose load, thyrotropin releasing hormone (TRH) and luteinizing hormone releasing hormone (LHRH) have also been reported. The effect of reduced leptin levels on GH hypersecretion in AN is still unclear, but ghrelin (the gastric hormone that is a natural ligand of the GH secretagogue receptor and strongly stimulates somatotroph secretion) is thought to play a major role. Regardless of the supposed central and peripheral alterations, it has to be emphasised that the activity of the GH/IGF-I axis in AN is generally restored by nutritional and stable weight gain. It therefore reflects an impaired nutritional state and cannot be considered a primary hallmark of the disease.
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PMID:GH/IGF-I axis in anorexia nervosa. 1764 63


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