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Regulated expression of GATA-6 transcription factor in gastric endocrine cells.

BACKGROUND & AIMS: GATA transcription factors may regulate gene expression in developing tissues, including gut epithelium. In the stomach, their expression has been linked to regulation of proton pump genes. However, GATA consensus sequences also occur in the promoter of the histidine decarboxylase gene, located in enterochrommafin-like cells. The aim of this study was to determine if GATA factors are located in gastric endocrine cells and to examine their expression during development and in response to changes in the gastric luminal environment. METHODS: Polymerase chain reaction cloning, Northern blot, and gel shift assays were used to examine GATA expression in gastric endocrine cells; changes in GATA messenger RNA during development and in response to fasting, feeding, and gastric achlorhydria were determined by Northern blot. RESULTS: GATA-6 was expressed strongly in rodent gastric endocrine cell fractions, in a human ECL cell tumor, and in an endocrine cell line (STC-1) derived from gut epithelium; proteins from STC-1 cells bound specifically to GATA consensus sequences in the human histidine decarboxylase promoter. GATA messenger RNA abundance was up-regulated during terminal differentiation of the rat stomach and on feeding after a fast. CONCLUSIONS: The GATA-6 transcription factor is expressed in gastric endocrine cells and is a potential regulator of gastric differentiation and of genes involved in the response to feeding.

Achlorhydria↗

[The morphological characteristics of endocrine-cell cancers of the large intestine].

Histological variants of colon carcinoma depending upon the quantity of endocrine cells are distinguished on the basis of 66 malignant epithelial colon tumours morphological investigation. Special emphasis was made on the characteristics of the endocrine cell carcinoma, combined tumours with a combination of glandular and endocrine components, and amphicrin neoplasms. A trabecular-glandular variant of endocrine cell carcinoma is found to be predominant in the colon. The criteria are suggested for the identification of endocrine-cell tumours.

APUD Cells↗

Mucosal argyrophil endocrine cells in pernicious anaemia and upper gastrointestinal carcinoid tumours.

The number and density of argyrophil endocrine cells were morphometrically calculated in gastric fundal mucosal biopsy specimens taken from 64 patients with pernicious anaemia (five with gastric carcinoids, 15 with nodular argyrophil cell hyperplasia, 44 with diffuse argyrophil cell hyperplasia) and from 14 healthy controls. Similar calculations were also made on the ileal mucosa away from the tumour of 10 patients with ileal carcinoids and 10 controls. In the stomach, the argyrophil cell counts were twice as high in the patients with pernicious anaemia than in controls and the densities in the whole mucosa or in the epithelial structures were similarly three to five times higher. The cell counts in the patients showed positive correlation with the serum gastrin concentration. The patients with nodular argyrophil cell hyperplasia and gastric carcinoids formed a uniform group with the highest cell counts and serum gastrin concentrations; the difference between the groups was in the longer duration of pernicious anaemia in the patients with carcinoid tumours. On the other hand, no endocrine cell hyperplasia was seen in those with ileal carcinoids. It is concluded that fundal mucosal endocrine cells show an increase in patients with pernicious anaemia that is related to the gastrin concentration. This phenomenon may favour the development of hyperplastic endocrine cell nodules and, eventually, carcinoid tumours.

Adult↗

Insulin-, glucagon-, and somatostatin-immunoreactive endocrine cells in the equine pancreas.

Equine pancreas was investigated with immunohistochemical methods to study the distribution of endocrine cells immunoreactive to anti-insulin, anti-glucagon, and anti-somatostatin. A-cells demonstrable by anti-glucagon are located in the center of Langerhans islets and frequently in the duct epithelium. Few A-cells are seen associated to acini. Anti-insulin reactive B-cells form a large zone around the center of the Langerhans islets in which some B-cells lie between exocrine cells and others, although few, are located in the duct epithelium. D-cells stained with anti-somatostatin serum form a discontinuous outermost zone around the Langerhans islets. In some islets the D-cells are also observed among the B-cells or between the border of A- and B-cells. Single D-cells are seen in the duct epithelium or between acinar cells. In younger horses, endocrine cells are more frequently associated in bulges of the duct system. The histotopographic relation between these endocrine cell types is discussed with respect to its functional significance.

Animals↗

An immunohistochemical study of endocrine cells in the alimentary tract of the grass lizard, Takydromus wolteri Fischer (Laceridae).

Distribution patterns and the relative frequency of different types of endocrine cells were demonstrated in the alimentary tract of the grass lizard, Takydromus wolteri, using nine specific antibodies raised against mammalian regulatory peptides. The alimentary tract of the lizard was divided into six portions from the esophagus to the rectum. Most endocrine cells were found in the epithelial lining and were generally spindle shaped with long cytoplasmic processes ending in the lumen (open cell type), whereas cells that were spherical in shape (closed cell type) were occasionally found in gastric, esophageal and intestinal glands. Endocrine cells were stained for the following regulatory peptides: bovine Sp-1/chromogranin (BCG), serotonin, somatostatin, gastrin, cholecystokinin (CCK)-8, glucagon, insulin, human pancreatic polypeptide (HPP) and secretin. Cells stained for BCG and serotonin were present throughout the entire gastrointestinal tract and they occurred with the highest frequency in stomach and pylorus, respectively. Somatostatin-positive cells were detected throughout the entire gastrointestinal tract except for the esophagus and large intestine, and were most predominant in pylorus and duodenum. Cells stained for gastrin were restricted to the pylorus and duodenum and occurred with a relatively low frequency. CCK-8-positive cells were observed from pylorus to small intestine and showed the highest frequency in the pylorus. Glucagon- and insulin-containing cells were located in duodenum and small intestine but were found only rarely. HPP-stained cells were detected in duodenum and small intestine with the highest frequency in duodenum. Cells stained for secretin were restricted to duodenum and were found only rarely. In conclusion, distribution patterns and the relative frequency of these endocrine cells correspond well with previous reports on distribution patterns of endocrine cells in reptile species but some deviating patterns were also observed.

Animals↗

Fatty acids stereospecifically stimulate neurotensin release and increase [Ca2+]i in enteric endocrine cells.

In primary cultures of canine enteric endocrine cells, fatty acids directly stimulated the release of neurotensin-like immunoreactivity (NTLI). This stimulatory effect was cell specific, selective for long-chain unsaturated fatty acids, and stereospecific. Saturated fatty acids of comparable chain length and trans isomers of long-chain unsaturated fatty acids had no effect on basal NTLI secretion. NTLI release in response to oleic acid (cis-11) was dose dependent with an apparent EC50 of 37 +/- 0.18 microM. Cyclooxygenase inhibitors had no effect on fatty acid-stimulated NTLI release, indicating the response was not mediated by the production of active arachidonic acid metabolites. Somatostatin (100 nM) inhibited maximal oleic acid-stimulated NTLI release by 92%. Long-chain unsaturated fatty acids also selectively and stereospecifically stimulated an increase in the mobilization of [Ca2+]i to 313.5 +/- 28.6% of resting [Ca2+]i. Staurosporine, an inhibitor of protein kinase C, dose dependently inhibited oleic acid-stimulated NTLI release with an IC50 value of 22 +/- 0.4 nM. Long-chain unsaturated fatty acids had no effect on basal NTLI secretion from rat pheochromocytoma cells and medullary thyroid carcinoma cells, two clonal lines that express NTLI. The cell-specific, selective stereospecific, and inhibitable action of fatty acids on NTLI secretion suggests that the effect of fatty acids on enteric endocrine cells is indicative of a receptor-mediated mechanism.

Adrenal Gland Neoplasms↗

[Ultrastructure of duodenal endocrine cells in children].

All ultrastructural varieties of endocrine cells, described in literature for adult persons, were revealed in the epithelium of the duodenal crypts of children at the age of 6--14 years. The cells form rather distinct groups in accordance with the International Classification, that speaks in favour of adequate application of the methods for processing the material and allows to compare the data obtained with those in literature. Endocrine cells in children, however, demonstrate greater polymorphism as their secretory granules differ in density even within a single cell. This phenomenon, along with detecting degenerative forms, demonstrates active functioning of this cell system in children.

Adolescent↗

Involvement of calpain and synaptotagmin Ca2+ sensors in hormone secretion from excitable endocrine cells.

The requirement for Ca(2+) to regulate hormone secretion from endocrine cells is long established, but the precise function of Ca(2+) sensors in stimulus-secretion coupling remains unclear. In the current study, we examined the expression of calpain and synaptotagmin in INS-1 pancreatic and GH3 and AtT20 pituitary cells, and investigated the sensitivity of hormone secretion from these cells to inhibition of the calpain family of cysteine proteases. Little difference in expression of mu-calpain was observed between the different endocrine cells. However, AtT20 cells did exhibit an extremely low abundance of both m-calpain and the 54 kDa isoform of calpain-10 relative to their expression in INS-1 and GH3 cells. Interestingly, secretagog-stimulated secretion from both INS-1 and GH3 cells was completely abolished following pre-incubation with the cysteine protease inhibitor E64, whereas stimulated secretion from AtT20 cells was modest and completely insensitive to E64 inhibition. These results are in stark contrast to synaptotagmin data. Synaptotagmin expression in AtT20 cells is abundant, whereas INS-1 cells express extremely low levels of this Ca(2+) sensor, relative to the pituitary cells. We hypothesize that the expression pattern of calpain and synaptotagmin isoforms may reflect alternative mechanisms of stimulus-secretion coupling in excitable endocrine cells.

Adrenocorticotropic Hormone↗

Glycoprotein hormone alpha subunit in endocrine cells of human oxyntic mucosa. Studies on its relation to neuroendocrine tumors.

Expression of the alpha-subunit of glycoprotein hormones is an acquired feature of the endocrine cells of the oxyntic mucosa in patients with sustained serum levels of gastrin, and may be related to the hyperplasia-carcinoid sequence occurring in these patients. In the present study we have investigated the intragastric cellular localization and the circulating levels of alpha-subunit in a patient with Zollinger-Ellison syndrome. In this patient we have found that: 1) Endocrine cells accounted for 2.29% +/- 1.44% of the total oxyntic mucosal volume (normal value: 0.9% +/- 0.4%), with the ECL cells representing 63.22% +/- 10.9% of the total endocrine cell volume (normal value: 29.8 +/- 8.8%). 2) Cells immunoreactive for the alpha-subunit were found to correspond ultrastructurally to a subpopulation of enterochromaffin-like cells, indistinguishable from similar cells devoid of significant immuno-electron microscopic labeling. 3) Immunoreactive cells included a portion of oxyntic endocrine cells with punctate granules, a feature previously observed only in carcinoid tumors of the oxyntic mucosa. 4) In consecutive sections of freeze-dried vapor-fixed biopsies a fraction of alpha-subunit storing cells was found to co-express histamine. 5) The serum alpha-subunit levels were abnormally elevated and paralleled those of gastrin in a secretin-stimulation test. Analysis of similar curves in two other patients with Zollinger-Ellison syndrome, and five patients with hypergastrinemic atrophic gastritis, all presenting alpha-subunit containing oxyntic endocrine cells, showed significant alpha-subunit elevations only in the patients with ulcerogenic syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastric Mucosa↗

An immunohistochemical study of gastrointestinal endocrine cells in the BALB/c mouse.

The distributions and frequencies of some endocrine cells in the eight portions of the gastrointestinal tract (GIT) of BALB/c mouse were studied. Endocrine cells were stained using immunohistochemical method with seven types of antisera against bovine chromogranin (BCG), serotonin, gastrin, cholecystokinin (CCK)-8, somatostatin, glucagon and human pancreatic polypeptide (HPP), and the regional distributions and their relative frequencies were observed in the eight portions of the GIT of BALB/c mice. All seven types of immunoreactive (IR) cells were identified. Most of the IR cells in the intestinal portion were generally spherical or spindle in shape (open type cell) while round-shaped cells (closed type cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies varied according to each portion of the GIT. BCG-IR cells were observed throughout the whole GIT except for the rectum and they were most predominant in the pylorus. Serotonin-IR cells were detected throughout the whole GIT and they showed the highest frequency in the fundus. Gastrin- and CCK-IR cells were restricted to the pylorus and duodenum with a majority in the pylorus and rare or a few frequencies in the duodenum. Compared with other mammals, somatostatin-IR cells were restricted to the fundus and pylorus with a few frequencies, respectively. In addition, glucagon- and HPP-IR cells were restricted to the fundus and duodenum, respectively, with relative low frequencies. Some species-dependent unique distributions and frequencies of endocrine cells were observed in the GIT of BALB/c mouse compared with other rodents.

Animals↗

Calbindin 28 kDa in endocrine cells of known or putative calcium-regulating function. Thyro-parathyroid C cells, gastric ECL cells, intestinal secretin and enteroglucagon cells, pancreatic glucagon, insulin and PP cells, adrenal medullary NA cells and some pituitary (TSH?) cells.

The distribution of calbindin in some endocrine glands (thyroid, parathyroid, ultimobranchial body, pituitary and adrenals) and in the diffuse endocrine cells of the gut and pancreas has been investigated immunohistochemically using an antiserum raised against the 28 kDa calbindin from chicken duodenum. The identity of calbindin-immunoreactive cells in a number of avian and mammalian species was ascertained by comparison with hormone-reactive cells in consecutive sections or by double immunostaining of the same section with both calbindin and hormone antibodies. Calcitonin-producing C cells of the mammalian and avian thyroid, parathyroid or ultimobranchial body, PP, glucagon and insulin cells of the mammalian and avian pancreas, enteroglucagon cells of the avian intestine, secretin cells of the mammalian duodenum, histamine-producing ECL cells of the mammalian stomach, as well as noradrenaline-producing cells of the adrenal medulla and some (TSH?) cells of the adenohypophysis were among the calbindin-immunoreactive cells. Although some species variability has been observed in the intensity and distribution of the immunoreactivity, especially in the pancreas and the gut, a role for calbindin in the mechanisms of calcium-mediated endocrine cell stimulation or of intracellular and extracellular calcium homeostasis is suggested.

Animals↗

Immunocytochemical and autoradiographic studies of the endocrine cells interacting with GABA in the rat stomach.

There are now increasing evidences suggesting that GABA is able of direct interaction with certain endocrine cells. In the present study, highly specific anti-GABA-glutaraldehyde antibodies and 3H-GABA uptake were used at the light and electron microscope levels to investigate the occurrence of cells containing endogenous GABA or taking up exogenous GABA in the mucosal antrum and corpus of the rat stomach. Only certain endocrine cell types of both regions were immunostained or grain-labelled. However, the morphology of their secretory granules did not allow to identify the nature of their hormone with certainty but suggested that somatostatin-like cells could interact with GABA. The combination of gastrin and somatostatin immunodetection with 3H-GABA uptake autoradiography at the light microscope level, revealed that a subpopulation of somatostatin-like cells and other still unidentified endocrine cells are able to take up GABA, while the gastrin-like cells are not. These results reinforce the hypothesis that certain endocrine cell types of the diffuse endocrine system of the digestive tract are able to directly interact with GABA.

APUD Cells↗

Human chorionic gonadotropin alpha-subunit in endocrine cells of fibrotic and neoplastic lung. Its mode of localization and the size profile of granules.

To investigate the nature of various endocrine cells immunoreactive for human chorionic gonadotropin (hCG alpha) in the lung, immunoelectron microscopic study was performed on fibrotic adult lungs and endocrine neoplasms of the lung. The mode of localization of hCG alpha and the size profile of hCG alpha granules were different among endocrine cells under various proliferative conditions. The population of hCG alpha granules in the grouped type of endocrine cells was more variable with a shift to smaller size (mean area: 1.395 x 10(-2) microns 2, mean maximum diameter: 149.8 nm), than that in solitary ones (1.493 x 10(-2) microns 2, 155.4 nm). Tumorlet endocrine cells had larger hCG alpha granules (1.800 x 10(-2) microns 2, 171.3 nm) without change of SD of size parameters. In carcinoid tumors, the size profile of hCG alpha granules was considerably different from that in the three types described above. Moreover, hCG alpha granules were significantly smaller in size in carcinoid tumors without lymph node metastasis (2.295 x 10(-2) microns 2, 189.8 nm) than those in malignant carcinoid tumors with metastasis (3.368 x 10(-2) microns 2, 230.5 nm). The population of hCG alpha granules in atypical endocrine tumor was the parallel shift to a larger scale (6.251 x 10(-2) microns 2, 307.5 nm) from that of malignant carcinoids and the distribution pattern was different from that in benign carcinoids. In small cell carcinoma of the lung, hCG alpha immunoreaction was preferentially present in perinuclear space and dilated rough endoplasmic reticulum. The mode of localization of hCG alpha and the size profile of hCG alpha granules, representing specific features of intracellular processing of hCG alpha, may be closely related with some qualitative changes in the neoplastic process of pulmonary endocrine cells.

Carcinoid Tumor↗

Localization of neuropeptides in endocrine cells of the chicken thymus.

Interactions between endocrine cells and epithelial cells, mediated by neurotensin, have been proposed in the chicken thymus. In this study, other neuropeptide candidates acting as mediators in the chicken thymus were examined immunohistochemically. Endocrine cells being oval, elongated or triangular in shape were immunoreactive with antibodies against methionine-enkephalin, neuropeptide Y, substance P, and vasoactive intestinal peptide. These findings suggest that 4 neuropeptides may be involved in cell-to-cell interactions in the chicken thymus.

Animals↗

Differentiation and proliferation of endocrine cells in the regenerating rat pancreas after 90% pancreatectomy.

The transplantation of pancreatic tissue has been anticipated to serve as a radical treatment for diabetes mellitus. However, the identification of the stem cells, and elucidation of their differential lineage and controlling mechanisms are prerequisites to ensure effective transplantation. We conducted an immunohistochemical study to determine the proliferation and differentiation dynamics of pancreatic endocrine cells in the rat pancreas 1 to 28 days after a 90% pancreatectomy. Regeneration of endocrine cells started immediately after pancreatectomy. The process of regeneration included the proliferation of preexisting islet cells and neogenesis of endocrine cells from epithelial cells of the most peripheral duct. Intercalated ductal cells and centroacinar cells were speculated to be the major sources of neogenesis, from which islet tissue was formed. Glucagon cells were the first endocrine cells differentiated, some of which transformed to insulin cells by a mechanism of non-replication. These results indicate that endocrine stem cells exist among the intercalated ductal and/or centroacinar cells, and these special regions should be utilized in transplantation for the successful treatment of diabetes.

Animals↗

Immunoreactive endocrine cells and nerve elements in the gut of the Italian cave salamander.

The presence and distribution of eleven different types of immunoreactive endocrine cells and nine types of immunoreactive nerve elements were immunohistochemically identified in the gut and pancreas of the italian cave salamander, Hydromantes ambrosii. The majority of gastrointestinal endocrine cells were of open-type, often presenting basal cytoplasmic processes. Gastrin- and substance P-immunoreactive cells in the fundus and bombesin-immunoreactive cells in the intestinal portion were instead of closed type. Immunoreactive nerve fibres were particularly numerous in the muscular layers and blood vessel wall; bombesin- and substance P-immunoreactive nerve fibres were also abundant beneath gastro-intestinal epithelium. Besides substance P-, caerulein- and cholecystokinin-immunoreactive nerve fibres, all the other immunopositive nerve fibres seemed to be of intrinsic types. By the use of four different gastrin/cholecystokinin antisera three variously distributed subpopulations of endocrine cells and nerve elements were detected. Most of the pancreatic endocrine cells were organised in chord-like islets, polarized in the direction of blood vessels. A sparse network of bombesin-immunoreactive fibres was also found in the pancreas. The distribution of bombesin- and of the gastrin/cholecystokinin-immunoreactive material in the stomach and the presence of closed type endocrine cells indicate a more evoluted organization of the gastroenteropancreatic neuroendocrine system thus confirming the position of Hydromantes ambrosii among the higher urodeles.

Animals↗

Studies on pituitary melanotrophs reveal the novel GABAB antagonist CGP 35-348 to be the first such compound effective on endocrine cells.

One obstacle to understanding the action and physiological significance of the responsiveness of various endocrine cells to gamma-aminobutyric acid (GABA) has been that previously available substances, all active as GABAB antagonists in the nervous system, are ineffective on endocrine cells. The introduction of a potent new member of this class, CGP 35-348, of very different chemical structure, encouraged us to examine its effect on endocrine cells. For this purpose, we studied melanotroph secretion from pituitary neurointermediate lobes. We found that CGP 35-348, in contrast to previously available members of this class, suppressed completely, in rat and toad, secretory responses to baclofen, the classic GABAB agonist. Analysis, in toad, showed CGP 35-348 did not affect responses to GABAA agonists (muscimol; isoguvacine), dopamine, or neuropeptide Y. When tested against GABA, the physiological ligand present in the innervation of melanotrophs (along with dopamine and neuropeptide Y), CGP 35-348 completely suppressed the secretory response, which, in toad, is purely inhibitory and unaffected by bicuculline, the specific GABAA antagonist. In addition, CGP 35-348 unmasked a stimulant effect that bicuculline blocked. In CGP 35-348, we thus have a new tool with which to analyse responses to GABA and their physiological involvement in endocrine cells.

Animals↗

Calcium and ionophore A23187 lower calcitonin gene-related peptide-like immunoreactivity in endocrine cells of organ cultured fetal rat lungs.

Small-granule endocrine cells differentiate in airway epithelium of intact and cultured fetal rat lungs. We noted that the cells store calcitonin gene-related peptide (CGRP) in vitro as well as in vivo and used the ionophore A23187 to test the effects of calcium on peptide secretion in this system. Lungs of 14-day and 15-day fetal rats, organ cultured for 6-9 days, were divided into groups of 5 explants each and incubated for 15 min at 37 degrees C in the basic medium containing 0 mM, 1 mM, or 10 mM CaCl2, with or without 8 microM A23187, or 10 mM EGTA. Intracellular CGRP in these explants was quantified by supraoptimal dilution peroxidase immunocytochemistry (Springall et al.: J. Pathol. 155:259-267, 1988): counts were made of endocrine cells stained with a 1/60,000 dilution of anti-CGRP and repeated on the same sections after restaining with antibody diluted at 1/1,000. Results, analyzed by Chi-square test, were expressed as % cells stained with antibody at 1/60,000 vs. those stained at 1/1,000. Immunoreactivity for CGRP was significantly reduced by A23187 in the presence of high extracellular Ca2+ (10 mM), the inference being that these cells secrete peptide hormones in response to Ca2+ influx across the plasma membrane. The organ cultures evidently can be used to assess certain physiological responses of lung endocrine cells in an accessible, relatively organotypical setting.

Animals↗