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)

Histochemical and ultrastructural studies were carried out in four gastric carcinoids, two of which were associated with atrophic gastritis and pernicious anemia. All tumors showed intense argyrophilia and vesicular granules resembling those of endocrine enterochromaffinlike (ECL) cells in normal human gastric mucosa. Tumor cells were found to be unreactive to all the 18 available antiserums to gut hormones, including gastrin, somatostatin, glucagon, and pancreatic polypeptides. The tumors were interpreted as ECL cell argyrophil carcinoids with the various degrees of differentiation and atypia.
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PMID:Gastric carcinoids of argyrophil ECL cells. 723 95

Before the discovery of Helicobacter pylori, duodenal ulcers were thought to be caused by excessive acid secretion. Duodenal ulcer patients have more parietal cells than controls. In addition, they cannot suppress their acid secretion when the gastric lumen is empty or acidic. These changes, plus an increase in the release of gastrin were attributed to a paucity of the inhibitory peptide somatostatin in the gastric mucosa. It has now been established that the paucity of somatostatin and the failure to suppress acid secretion are actually the result of H. pylori infection. In patients without duodenal ulcers H. pylori infection is often associated with decreased acid secretion. This occurs on first infection and also later because H. pylori gastritis predisposes to gastric atrophy.
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PMID:Helicobacter pylori, acid and gastrin. 760 Jan 35

The enterochromaffin-like (ECL) cell of the oxyntic, acid-secreting mucosa is at present the most extensively studied endocrine cell type in the gastrointestinal tract. It is functionally related to acid secretion through paracrine release of histamine. Its ability to undergo proliferation in response to the trophic stimulus of hypergastrinemia has important implications in pathology, being involved in the development of ECL-cell carcinoid tumors of rodents treated with powerful inhibitors of acid secretion as well as in that of most human gastric carcinoids which, with rare exceptions, are composed of ECL cells. The various aspects of the ECL-cell response to hypergastrinemia in humans are discussed in this review. The trophic effect of gastrin is specific for ECL cells and its sensitivity is enhanced by the female sex and by the genetic background of the multiple endocrine neoplasia type 1 (MEN-1) syndrome. Exposure of ECL cells to hypergastrinemia induces peculiar changes in the structure of cytoplasmic granules and triggers the phenotypic expression of a novel protein, the alpha subunit of glycoprotein hormones, absent in normal cells. The ECL-cell hyperplasia driven by hypergastrinemia may influence the hypersecretory gastric state of patients with Zollinger-Ellison syndrome (ZES) by inappropriate intramucosal secretion of histamine and may contribute to the high circulating levels of basic fibroblast growth factor (bFGF), an ECL-cell product responsible for parathyroid mitogenic effects in MEN-1 patients. However, hypergastrinemia per se cannot promote evolution of hyperplasia into carcinoid tumors, for which additional unknown factors, particularly associated with atrophic gastritis or MEN-1 syndrome, are required. ECL-cell carcinoids developing within these backgrounds have a strikingly more favorable course than their gastrin-independent counterpart. Suppression of hypergastrinemia, either by antrectomy or treatment with somatostatin analogues, may induce regression of both ECL-cell hyperplasia and gastrin-sensitive ECL-cell carcinoids.
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PMID:Hypergastrinemia and gastric enterochromaffin-like cells. 776 39

We conducted this study to identify the endocrine and neurocrine mechanisms of gastric mucosal protection in rats with experimental atrophic gastritis (erosive atrophic antritis) induced by prolonged exposure to taurocholate. This resulting gastritis was characterized by a significant reduction of parietal cell mass, a decrease in mucosal thickness, decreased numbers of pyloric glands, infiltration by inflammatory cells, and fibrotic proliferation in the gastric mucosa. Mucosal erosions were also prominent. These morphologic and morphometric findings indicate the presence of erosive atrophic gastritis, as previously described. Fasting levels of serum gastrin increased significantly in the rats with gastritis versus controls, whereas the mucosal gastrin levels did not differ significantly from those of controls. Mucosal levels of somatostatin decreased significantly, and vasoactive intestinal peptide (VIP) increased significantly in the pyloric sphincter region. These findings suggest that these peptides and neuropeptides are involved in the induction of this form of gastritis. The peptides may play an important role in the mechanisms of gastric mucosal protection (i.e., gastrin is an aggressive and somatostatin is a defensive factor, and VIP promotes the reflux of bile into the stomach by relaxing the pyloric sphincter).
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PMID:Further study of experimental gastritis in rats: endocrine and neurocrine profile. 790 87

In order to ascertain possible abnormalities in somatostatin and gastrin secretion in patients with duodenal ulcer, the author compared bombesin-stimulated somatostatin and gastrin secretion by antral mucosal explants in patients with duodenal ulcer, those with atrophic gastritis and normal controls. An organ culture technique was employed. This excluded neurogenic, hormonal and circulatory influences. Bombesin in concentrations of 10(-7) M to 10(-5) M stimulated gastrin and somatostatin secretion at a dose-dependent manner. In all subjects, bombesin (10(-7) M) stimulated antral gastrin release and increased explant gastrin content significantly (p < 0.05). Bombesin significantly increased somatostatin release and explant somatostatin content in normal subjects (p < 0.05) but not in patients with duodenal ulcer (p > 0.05). In the presence of bombesin, the total net increase of gastrin in medium and explants was greater in duodenal ulcer patients (31.57 +/- 5.20 ng/mg wet w.) compared with normal subjects (19.63 +/- 4.50 ng/mg wet w.) (p < 0.01). The total net increase of somatostatin in the presence of bombesin was significantly less in duodenal ulcer patients (0.10 +/- 0.02 ng/mg wet w.) than in normal subjects (1.45 +/- 0.24 ng/mg wet w.) (p < 0.01). The results suggest that abnormalities in somatostatin and gastrin secretion of the antrum contribute to the pathogenesis of increased gastric acid secretion in duodenal ulcer.
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PMID:Secretion of somatostatin and gastrin by human antral mucosa--an in vitro study in duodenal ulcer patients and control subjects under stimulation of bombesin. 809 23

The aim of the study was to evaluate whether treatment with 200 micrograms/d of the somatostatin analogue octreotide (SMS 201-995) for three months can influence the trophic action exerted by hypergastrinemia on endocrine cells of the oxyntic mucosa, a condition potentially leading to hyperplasia and carcinoid tumors. Endocrine cells were morphometrically investigated in Grimelius silver stained sections of endoscopic biopsies of oxyntic mucosa collected from 13 hypergastrinemic patients with Zollinger-Ellison syndrome (ZES) (n = 5), antral G cell hyperfunction (AGCH) (n = 4) and atrophic gastritis type A (AG-A) (n = 4) before and after 3 months treatment and 3 months after drug discontinuance. The treatment induced a reduction of the volume density (P < 0.015), profile cross sectional area (P < 0.05) and number of cell profiles per unit area (P < 0.015) of argyrophil cells. A rebound of all these parameters was observed 3 months after drug withdrawal with values usually exceeding those at the entry, except in cases of AG-A. The patients' plasma gastrin concentrations presented similar variations showing a significant relation with all morphometric parameters of argyrophil cells. Also, the cell content in alpha subunit of human chorionic gonadotropin was related to the plasma gastrin levels, a finding confirming the close gastrin dependence of the expression of this protein by oxyntic endocrine cells. No significant changes were observed in mucosal somatostatin D cells. These results indicate that variations in circulating gastrin levels are the most likely factor responsible for the hypotrophic effect of octreotide on oxyntic argyrophil cells (mostly corresponding to the ECL cells) of hypergastrinemic patients.
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PMID:Morphometry of gastric endocrine cells in hypergastrinemic patients treated with the somatostatin analogue octreotide. 823 12

Helicobacter pylori is the new-found cause of duodenal ulcers (DU), but acid secretion remains necessary and is elevated in DU patients. My group and others have asked whether H. pylori itself alters gastric physiology. This infection has been found to decrease local expression of the inhibitory peptide somatostatin, and to increase release of the acid-stimulating hormone gastrin. H. pylori infection can alter acid secretion in both directions. Acid disappears temporarily on first infection, and may dwindle later if H. pylori causes gastric atrophy. DU patients have approximately twice the normal parietal cell mass, which increases their maximal secretory capacity, but it is not clear whether or not this is due to H. pylori. However, the infection certainly does change physiological control of acid secretion, as expected from the endocrine changes. Acid secretion is elevated during fasting, during stimulation with an acidic meal and during infusions of gastrin-releasing peptide. The balance between these opposing effects of H. pylori on acid may be crucial in determining the clinical outcome of H. pylori infection. High-acid secretion leads to DUs whilst low acid secretion is found in patients with gastric ulcers and gastric cancer. Inflammatory cytokines released in H. pylori gastritis may cause some of these changes in gastric physiology.
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PMID:The somatostatin-gastrin link of Helicobacter pylori infection. 854 Oct 34

Research is asking how H. pylori causes diseases, and also why the same bacteria produces different conditions in different persons. The process involves bacterial factors and the host's response. Some bacterial factors such as urease are produced by all strains of H. pylori. This enzyme may damage the gastric epithelium by practically releasing ammonia. Other bacterial factors such as vacuolating toxin are only produced by some strains, and these strains are more likely to cause ulcers or cancer. The host's response has been studied by physiologists, immunologists, and histologists, but the separation of systems is artificial. For example, physiologists find that H. pylori stops gastric D-cells from expressing somatostatin normally, which impairs reflex inhibition of acid secretion, but the D-cell malfunction is probably due to inflammatory factors. In H. pylori gastritis, the gastric epithelial cells behave like immunocytes and express class II molecules and cytokines such as interleukin-8. The patient's histological response to H. pylori is quite closely related to the disease outcome. Patients who respond by developing gastric atrophy are more likely to get gastric ulcers or stomach cancer, but patients whose gastric corpus remains healthy tend to secrete more acid and develop duodenal ulcers, particularly if they have gastric metaplasia in their duodenum. Studies of disease mechanisms provide a valuable insight into the development of these common diseases, and may enable us to identify at-risk groups who particularly merit eradication therapy.
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PMID:Pathogenic mechanisms. 856 49

The effects of long term (6-month), high (500-micrograms), once a day administration of octreotide on enterochromaffin-like (ECL) cell proliferation were evaluated in eight patients with hypergastrinemic atrophic gastritis at risk for the development of gastric carcinoids. Fasting gastrin levels were determined during treatment and up to 6 months after the end of treatment. Chromogranin A, hCG alpha, and somatostatin-immunostained cells were morphometrically evaluated in biopsy specimens of corpus mucosa taken before and after treatment. The results showed that gastrin levels significantly decreased from 950 to 238 ng/L (-74.9%; P < 0.01) at the end of treatment, a decrease that persisted 6 months after the end of treatment (450 ng/L; P < 0.05). The volume density of CgA cells (mostly ECL cells) decreased from 3.7% to 2.1% of the epithelial component (-43%; P < 0.014), that of hCG alpha-storing ECL cells decreased by 85% (P < 0.0007), and that of somatostatin-stained cells decreased by 74% (P < 0.04). No clinically significant side-effects were found. It is concluded that octreotide treatment as used in the present study is safe and effective in reducing hypergastrinemia and associated ECL cell changes in patients with atrophic gastritis. The decrease in D cells is consistent with the occurrence of somatostatin receptors and related autocrine regulation in these cells.
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PMID:Effectiveness of octreotide in controlling fasting hypergastrinemia and related enterochromaffin-like cell growth. 863 88

Carcinoids of the stomach, duodenum, and pancreas are represented by a variety of tumors with variable histologic and clinical features. Multicentric gastric carcinoids and concomitant nonantral argyrophilic hyperplasia are common in chronic atrophic gastritis, more rarely due to a multiple endocrine neoplasia (MEN)-related Zollinger-Ellison syndrome (ZES). These tumors are infrequently associated with metastases and may generally be dealt with by repeated endoscopic fulguration. Sporadic carcinoids tend to be larger, invasive, and more often metastatic, especially in the presence of atypical histology. Small tumors may be removed by endoscopy, but larger lesions need to be surgically excised. In association with metastases a histamine-related atypical carcinoid syndrome may evolve and require treatment with a somatostatin analog. Poorly differentiated neuroendocrine carcinomas of the stomach constitute markedly aggressive tumors that rarely are suitable for radical surgery. Gastrinomas are the most prevalent duodenal carcinoids and a common cause of ZES especially in MEN-I. Despite a marked tendency for regional lymph node dissemination, liver metastases occur late and duodenal gastrinomas are often excisable, thereby offering favorable odds for cure in ZES. Unusual somatostatin-rich carcinoids in the ampulla of Vater relate to von Recklinghausen's disease and may be the cause of obstructive jaundice; depending on their size, these tumors may be removed by local excision or pancreaticoduodenectomy. Gangliocytic paragangliomas are unusual, generally benign lesions of the duodenum. Rare pancreatic tumors with serotonin immunoreactivity may be classified as carcinoids and constitute an unusual cause of the carcinoid syndrome.
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PMID:Management of carcinoid tumors of the stomach, duodenum, and pancreas. 866 14


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