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)

At least 16 types of endocrine-paracrine cells have been identified ultrastructurally in the gastrointestinal mucosa. The production of hormones and local messengers such as 5-hydroxytryptamine, gastrin, cholecystokinin, somatostatin, secretin, gastric inhibitory peptide (GIP), enteroglucagon (glicentin, GLI), motilin, neurotensin, substance P and the enkephalins, by these cells, has been established. Progress has also been made in cytological studies of gut and pancreatic endocrine tumours. Argentaffin EC cell carcinoids, gastrinomas (of several ultrastructurally different varieties of gastrin cells), L-cell tumours and D-cell tumours are among those cytologically and functionally defined in the gut. Functionally undefined tumours include the so-called non-argentaffin carcinoids arising in various parts of the gut, some of which have been characterised cytologically as gastric ECL cell tumours and gastroduodenal P-D1-cell tumours. Gastrinomas, vipomas and rare argentaffin carcinoids are among gut-related pancreatic endocrine tumours. Non-functional paragangliomas, usually with some neuromatous component, occur in the duodenal wall. Extrapancreatic vipomas display ultrastructural features of ganglioneuroblastomas with peptidergic granules.
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PMID:The diffuse endocrine-paracrine system of the gut in health and disease: ultrastructural features. 611 45

Prospective screening was carried out in 12 members of three families with multiple endocrine adenopathies, type I (MEA,I) and in 14 patients with no multiple endocrine adenopathies with and without other endorcinopathies. Elevated basal and responsive (after a meal) plasma concentrations of a relatively new candidate-hormone, human pancreatic polypeptide (hPP), were associated with pancreatic apudoma tumors in three asymptomatic patients with multiple endocrine adenopathies, type I. Two of these patients had excision of the tumors that resulted in normal plasma hPP concentrations postoperatively. Both tumors contained hPP predominantly by immunocytochemistry; one, a pure pancreatic polypeptide apudoma, was studied extensively demonstrating also by radioimmunoassay a high content of hPP and negligible amounts of insulin, glucagon, somatostatin, vasoactive intestinal polypeptide and gastrin. In this patient plasma concentrations of other polypeptides including insulin, glucagon, somatostatin, vasoactive intestinal polypeptide, gastrin, parathyrin, thyrocalcitonin, prolactin, corticotropin, growth hormone, thyrtropin and amine, serotonin, were within normal limits. The other patient, after excision of an hPP-detected pancreatic mixed hPP-gastrinoma, also became eugastrinemic postoperatively. Normal basal plasma hPP concentrations, but with exaggerated hPP responses to a meal in 11 patients, were associated with various combinations of islet cell hyperplasia, antral G cell hyperplasia with moderate hypergastrinemia and parathyroid hyperplasia. The patients with multiple endocrine adenopathies who have demonstrated this type of increased hPP response to a meal have not been operated on but are at risk for islet hyperplasia. Four of the 12 patients with multiple endocrine adenopathies, type I, with both normal basal and normally responsive hPP concentrations have no evidence as yet of pancreatic involvement.
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PMID:Pancreatic polypeptide as screening marker for pancreatic polypeptide apudomas in multiple endocrinopathies. 624 7

Gastropancreatic neuroendocrine cells synthesize large amounts of gamma-aminobutyric acid (GABA). This amino acid neurotransmitter appears to be stored in and released from, vesicles similar to small synaptic vesicles. So far, the function of GABA in gastropancreatic, neuroendocrine cells has not been clarified. Previous work suggested that only pancreatic, glucagon-producing alpha 2 cells contain functional GABAA receptors. Using subunit-specific antibodies in sections of human antral mucosa, a human gastrinoma and rat pancreas, we show that expression of GABAA receptors is abundant in gastropancreatic, neuroendocrine cells. Using the patch-clamp technique in the whole-cell mode we demonstrate that both the rat insulinoma cell line RIN 38 and the amphicrine cell line AR42J express functional GABAA receptors, which are characterized by a relatively low benzodiazepine and Zn2+ sensitivity and by an insensitivity to the inverse benzodiazepine agonist 6,7-alpha-methoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM). In contrast to neurons, activation of GABAA receptors leads to a membrane depolarization. This depolarization presumably activates voltage-gated Ca2+ channels, resulting in an increase in cytosolic Ca2+ concentration, [Ca2+]i, as shown with the fluorimetric dye fura-2. The combination of GABA release, GABAA receptor activation and the [Ca2+]i increase could constitute an autocrine mechanism, modulating the release of hormones such as gastrin, insulin and somatostatin.
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PMID:Expression of functional GABAA receptors in neuroendocrine gastropancreatic cells. 749 Dec 62

Requisites for preoperative and intraoperative tumor localization with [111In]diethylenetriaminepentaacetic acid-D-[Phe1]-octreotide scanning were explored in 23 patients with endocrine tumors (15 carcinoids, 4 insulinomas, and single cases of gastrinoma, medullary thyroid carcinoma, aldosteronoma, and paraganglioma). The patients were subjected to Octreoscan single photon emission computed tomographic examination prior to surgery and well counter investigation of nuclide uptake in tumors and normal tissues sampled at surgery. Somatostatin receptor-positive tumors demonstrated efficient nuclide accumulation with mean tumor:blood radioactivity ratios of 180-370 (for carcinoids and insulinoma), compared with tissue:blood ratios of 302 for spleen, 42 for liver, and < 10-15 in other normal tissues (pancreas, small intestine, and mesenteric fat). Inefficient preoperative visualization of lesions was related to inconspicuous size, as for primary intestinal carcinoids, tiny liver metastases, and a single small insulinoma. High background activity, pronounced tumor fibrosis, and meager accumulation of tracer also interfered with visualization. Tumor deposits in organs with low background activity (such as carcinoid mesenteric metastases and endocrine pancreatic tumors) were generally most readily detected. Intraoperative investigations with hand-held gamma detector probes were disturbed by obvious high background activity. These investigations revealed two preoperatively unrecognized primary intestinal carcinoids, which, however, were both palpable during surgery. These studies, therefore, had little impact on the surgical strategy.
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PMID:Human biodistribution of [111In]diethylenetriaminepentaacetic acid-(DTPA)-D-[Phe1]-octreotide and peroperative detection of endocrine tumors. 749 48

In a 66-year old woman, who suffered from recurrent melena, diarrhea and hematemesis with multiple untreatable gastric and duodenal ulcers, a markedly increased basal and secretin-stimulated gastrin level, clinically a Zollinger-Ellison syndrome was assumed. The conventional diagnostic procedures (esophago-gastro-duodenoscopy, colonoscopy, endosonography, ERCP, abdominal CT and small bowel enema) had failed to reveal the localisation of any gastrinoma. The thereupon performed scintigraphy with In-111-pentetreotide showed four somatostatin receptor expressing liver lesions: two of them could be detected at first site in the consecutively performed MR scans, another retrospectively bearing in mind the scintigraphic images. Today, the somatostatin receptor imaging seems to be a highly sensitive procedure for detecting and localizing hormonally active gastroenteropancreatic tumors. At the same time it is a method for in vivo evaluation of the somatostatin receptor status of localized GEP tumors, thus delivering a decisive diagnostic step for the evaluation of the effectiveness of a therapy with somatostatin analogues before such an expensive therapy is started.
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PMID:[Somatostatin receptor scintigraphy in neuroendocrine tumors exemplified by a patient with hepatic metastases of gastrinoma]. 751 13

To further investigate the antineoplastic efficacy and safety of somatostatin analogues, 2 trials were performed. Octreotide, SMS 201-995 (Sandostatin), was escalated in doses ranging from 1,500 micrograms to 6,000 micrograms daily in 14 patients with carcinoid. Somatuline, (BIM 23014C, Angiopeptin, Lanreotide) was given in doses ranging from 2,250 micrograms to 9,000 micrograms daily to 13 neuroendocrine patients (6 carcinoid, 2 atypical carcinoid, 3 pancreatic islet cell and 2 small cell lung cancer patients). All patients successfully completed dose escalations without significant adverse effects and were evaluable for toxicity. The dose limiting side-effect of octreotide was the injection volume. No dose limiting adverse effects have been observed with somatuline. Carcinoid syndrome symptoms were better controlled with higher octreotide doses. Thirteen patients were evaluable for octreotide's antitumor efficacy with a partial response observed in 4 (31%), stable disease in 2 and progressive disease in 7 patients. Radiographic changes of increased tumor necrosis occurred in 5 patients and was independent of response. Somatuline resulted in a partial response in 4 patients (2 carcinoids, 1 gastrinoma and 1 small cell lung cancer) (31%), stable disease in 1 atypical carcinoid, and progressive disease in 8 (4 carcinoid, 1 atypical carcinoid, 2 islet cell and 1 multi-drug resistant small cell lung cancer). Six of the 8 carcinoid patients had radiographic changes of increased necrosis. Dose escalation of somatostatin analogues is well tolerated and may be associated with antitumor activity in some neuroendocrine neoplasms.
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PMID:Somatostatin analogue phase I trials in neuroendocrine neoplasms. 768 64

The place of the long-acting somatostatin analogue octreotide in the management of symptoms in patients with functional gastroenteropancreatic (GEP) tumors and of growth in patients with metastatic disease is reviewed in this report. Numerous studies indicate that octreotide is, currently, the therapeutic principle of first choice in the symptomatic treatment of patients with carcinoid syndrome, Verner-Morrison syndrome and glucagonoma syndrome but not of insulinoma and gastrinoma patients. A beneficial effect on tumor growth has been demonstrated in 40% of patients with metastatic GEP tumor with stabilization of the disease as the most favorable response. However, further studies have to identify subgroups of patients in whom octreotide alone or in combination with alpha-interferon inhibits tumor growth.
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PMID:Management of gastroenteropancreatic endocrine tumors: the place of somatostatin analogues. 769 32

Neuroendocrine tumors of the gastroenteropancreatic system represent a group of tumors with various diagnostic problems. Especially detection of primary tumor lesions is often difficult. Endoscopic ultrasonography is a relatively new imaging procedure localizing insulinomas preoperatively in about 90% of cases. Thus, previously used invasive preoperative imaging methods are usually unnecessary. The combination of endoscopic ultrasonography and somatostatin receptor scintigraphy allows visualization of gastrinomas in 90% of cases. Somatostatin receptor scintigraphy can also visualize metastatic lesions of gastrinomas and carcinoids in the whole body with high accuracy. In surgical management of a gastrinoma, duodenal transillumination and intraoperative ultrasound should be performed in all cases to exclude small duodenal or periduodenal, extrapancreatic tumors. US, CT, and MRI should be mainly used to exclude local and distant metastases. Angiography is helpful in detecting anatomical variations of abdominal vessels preoperatively. Due to the excellent results of endoscopic ultrasonography and somatostatin receptor scintigraphy in localizing insulinomas and gastrinomas, transhepatic portal venous sampling appears to be obsolete.
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PMID:[Imaging methods in diagnosis of neuroendocrine tumors of the gastrointestinal tract]. 775 24

Recent evidence has shown that endocrine tumors are under an endocrine and an immune regulation, and that biotherapies with interferon or the long-acting somatostatin analog octreotide may be effective in the control of tumor growth and clinical symptomatology. Within the biotherapies of tumors, interleukin-2(IL-2) has appeared to play an essential role in the antitumor immune response. Despite its important antitumor role, very few studies have been carried out to investigate the possible use of IL-2 in the treatment of advanced endocrine tumors. Its potential toxicity would represent the main limiting factor for the clinical experiments with IL-2. Our previous studies have shown that the pineal hormone melatonin (MLT) may amplify the antitumor activity of IL-2, either through immunomodulating mechanisms or through a direct cytostatic activity by inhibiting tumor growth factor production. On this basis, we have performed a phase II pilot study with low-dose IL-2 plus MLT in 14 patients with untreatable endocrine tumors because of disseminated disease, lack of response to previous standard biotherapies or chemotherapies, or tumors for whom no effective therapy is available. Thyroid cancers, carcinoid and endodrine pancreatic tumors were the most frequent neoplasms. IL-2 was given at 3 million IU/day s.c. at 8 p.m. for 6 days/week for 4 weeks, corresponding to one cycle. MLT was given orally at 40 mg/day at 8 p.m. every day. In nonprogressed patients, a second cycle was given after a 21-day rest period. Patients were considered as evaluable when they received at least one complete cycle, and 12 patients were fully evaluable. According to WHO criteria, a partial response was achieved in 3/12 (25%) patients (carcinoid tumor: 1; neuroendocrine lung tumor: 1; pancreatic islet cell tumor: 1). Another patient with gastrinoma had a more than 50% reduction of tumor markers. Toxicity was low in all patients. This preliminary study suggests that low-dose IL-2 immunotherapy in association with the pineal hormone MLT may constitute a new well-tolerated and potentially active therapy of untreatable advanced endocrine tumors.
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PMID:Immunoendocrine therapy with low-dose subcutaneous interleukin-2 plus melatonin of locally advanced or metastatic endocrine tumors. 785 78

In the present study we investigated the effects of the somatostatin (SS) analogs octreotide, RC-160, and BIM-23014 on GH release by cultured cells of human GH-secreting pituitary tumors, in normal rat anterior pituitary cells, and on gastrin release by cultured cells from a human gastrinoma. In all GH-secreting adenomas and in rat anterior pituitary cells, RC-160 was the most potent compound. RC-160 significantly inhibited GH-, PRL, and/or alpha-subunit release by human GH-secreting pituitary adenoma cells in concentrations as low as 10(-12)-10(-14) M, whereas at the same concentrations, octreotide and BIM-23014 did not inhibit or were significantly less effective in inhibiting GH release (P < 0.01, RC-160 vs. octreotide and BIM-23014). In rat anterior pituitary cell cultures, the IC50 values for inhibition of GH release were, in rank order of potency, 0.1, 5.3, 47, 48, and 99 pM for RC-160, SS-14, BIM-23014, octreotide, and SS-28, respectively. Maximal inhibitory effects by the three analogs were the same in the human GH adenoma cell cultures and the rat anterior pituitary cell cultures (-60%). On the basis of these data, RC-160 appears to be about 500 times more potent than octreotide and BIM-23014 in inhibiting GH release by rat anterior pituitary cells in vitro. Forskolin (100 microM) as well as pretreatment of the cells with pertussis toxin significantly diminished the inhibitory effects of the three SS analogs and those of SS-14 and SS-28 to the same extent. The latter data suggest that octreotide, RC-160, and BIM-23014 act mainly via a pertussis toxin-sensitive G-protein and an adenylyl cyclase-dependent mechanism. In the human gastrinoma culture, RC-160 inhibited gastrin release significantly more than octreotide at 10(-12)- and 10(-14)-M concentrations (P < 0.01). In conclusion, the SS analogs octreotide, RC-160, and BIM-23014 may have significant different potencies of inhibition of hormone release in vitro, with RC-160 being the most potent SS analog and octreotide and BIM-23014 having similar potencies. Depending on the pharmacokinetic properties of these three octapeptide SS analogs, these observations may have consequences for the medical therapy of patients with SS receptor-positive endocrine tumors.
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PMID:Relative potencies of the somatostatin analogs octreotide, BIM-23014, and RC-160 on the inhibition of hormone release by cultured human endocrine tumor cells and normal rat anterior pituitary cells. 790 31


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