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PubMed2002

Neurogenin3 is differentially required for endocrine cell fate specification in the intestinal and gastric epithelium.

Endocrine cells of the pancreas and the gastrointestinal tract derive from multipotent endodermal stem cells. We have shown previously that the basic helix- loop-helix (bHLH) transcription factor neurogenin3 (ngn3) is required for the specification of the endocrine lineage in uncommitted progenitors in the developing pancreas. We investigate herein the expression and the function of ngn3 in the control of endocrine cell development in the intestinal and gastric epithelium. Our results indicate that as in the pancreas, gastrointestinal endocrine cells derive from ngn3-expressing progenitors. Mice homozygous for a null mutation in ngn3 fail to generate any intestinal endocrine cells, and endocrine progenitor cells are lacking. The other main intestinal epithelial cell types differentiate properly. In contrast, in the glandular stomach, the differentiation of the gastrin- (G cells) and somatostatin (D cells)-secreting cells is impaired whereas serotonin- (enterochromaffin EC cells), histamine- (enterochromaffin-like ECL cells) and ghrelin (X/A cells)-expressing cells are still present. Thus, ngn3 is strictly required for endocrine cell fate specification in multipotent intestinal progenitor cells, whereas gastric endocrine development is both ngn3 dependent and independent.

Animals↗
PubMed2000

Characterization of pancreatic endocrine cells of the European common frog Rana temporaria.

To characterize the endocrine cell types of the pancreas of Rana temporaria, conventional staining, silver impregnation, and immunocytochemical methods for light and electron microscopy have been applied to paraffin, thin and semithin sections, many of them serial pairs. Quantitative data on the frequency and distribution (insular, extrainsular among the exocrine cells, or within the pancreatic ducts) of each endocrine cell type are also reported. Four distinct endocrine cell types have been identified: insulin (B) cells, which are also immunoreactive for [Met]enkephalin; glucagon/PP (A/PP) cells, also immunoreactive for GLP1; somatostatin (D) cells; and a fourth endocrine-like cell type (X cells) of unknown content and function. X cells display characteristic ultrastructure and tinctorial traits but are nonimmunoreactive for all of the 37 antisera tested. The presence of [Met]enkephalin in amphibian pancreatic endocrine cells is now reported for the first time. Almost half (44.9 +/- 7.9) of the total endocrine cell population lies outside the islets, mainly spread among the exocrine cells. Approximately 37.2 +/- 4.6% of the total endocrine cell population was immunoreactive for insulin, 48.8 +/- 6.9% was immunoreactive for glucagon/PP, and 14.0 +/- 4.9% was immunoreactive for somatostatin; 79.2 +/- 6.4% of glucagon/PP cells are found within the exocrine parenchyma, representing the majority (86.4 +/- 4.3%) of extrainsular endocrine component. On the contrary, most B cells (94.2 +/- 2.1%) are located within the islets; 30.8 +/- 12.9% of D cells are found outside the islets.

Animals↗
PubMed2007

Regulation of pancreatic endocrine cell differentiation by sulphated proteoglycans.

AIMS/HYPOTHESIS: Epithelium-mesenchyme interactions play a major role in pancreas development. Recently, we demonstrated that embryonic pancreatic mesenchyme enhanced progenitor cell proliferation but inhibited endocrine cell differentiation. Here, we investigated the role played by sulphated proteoglycans, which are known to be essential to embryonic development, in this inhibitory effect. MATERIALS AND METHODS: We first determined the expression of the genes encoding glypicans, syndecans and the main glycosaminoglycan chain-modifying enzymes in immature embryonic day (E) 13.5 and more differentiated E17.5 rat pancreases. Next, using an in vitro model of pancreas development, we blocked the action of endogenous sulphated proteoglycans by treating embryonic pancreases in culture with chlorate, an inhibitor of proteoglycan sulphation, and examined the effects on pancreatic endocrine cell differentiation. RESULTS: We first showed that expression of the genes encoding glypicans 1, 2, 3 and 5 and heparan sulphate 2-sulfotransferase decreased between E13.5 and E17.5. We next found that alteration of proteoglycan action by chlorate blocked the inhibitory effect of the mesenchyme on endocrine differentiation. Chlorate-treated pancreases exhibited a dramatic increase in beta cell number in a dose-dependent manner (169-and 375-fold increase with 30 mmol/l and 40 mmol/l chlorate, respectively) and in alpha cell development. Insulin-positive cells that developed in the presence of chlorate exhibited a phenotype of mature cells with regard to the expression of the following genes: pancreatic and duodenal homeobox gene 1 (Pdx1), proprotein convertase subtilisin/kexin type 1 (Pcsk1; previously known as pro-hormone convertase 1/3), proprotein convertase subtilisin/kexin type 2 (Pcsk2; previously known as pro-hormone convertase 2) and solute carrier family 2 (facilitated glucose transporter), member 2 (Slc2a1; previously known as glucose transporter 2). Finally, we showed that chlorate activated endocrine cell development by inducing neurogenin 3 (Neurog3) expression in early endocrine progenitor cells. CONCLUSIONS/INTERPRETATION: We demonstrated that sulphated proteoglycans control pancreatic endocrine cell differentiation. Understanding the mechanism by which sulphated proteoglycans affect beta cell development could be useful in the generation of beta cells from embryonic stem cells.

Animals↗
PubMedDate not supplied

[Endocrine-cell stomach tumors].

Screening of the endocrine cell participation in the stomach carcinoma has been performed. Endocrine cells are found in all stomach tumors and those in which these cells occupy more than 75% of the surface are distinguished as endocrine cell carcinomas (ECC). They are subdivided into well (WD), moderately (MD) and poorly differentiated (PD). ECC are more frequently observed in males, their predominant location is cardia and fundus. The growth in the deep parts of mucosa and submucosa (this determines late clinical symptoms) is characteristic for these tumors. Alveolar, trabecular and glandular structural variants are observed in WD ECC and MD ECC, while PD ECC corresponded to small cell carcinoma (iat cell and intermediate types). Prognosis is unfavorable in MD ECC and PD ECC. Apart from this amacrine and combined tumors with an endocrine component are described. The authors emphasize the necessity to single out ECC from whole group of stomach carcinoma.

Apudoma↗
PubMed2004

The "normal" endocrine cell of the gut: changing concepts and new evidences.

The endocrine cells of the gut are a highly specialized mucosal cell subpopulation. Within the gastrointestinal tract at least 14 different cell types produce a wide range of hormones with a specific regional distribution. The gut endocrine cells belong to the diffuse endocrine system. These cells present two regulated pathways of secretion characterized by large dense core vesicles (LDCV) and synaptic-like microvesicles (SLMV). Gut endocrine cells are recognized by the expression of several "general" markers, including the LDCV marker chromogranin A and the SLMV marker synaptophysin, in addition to the cytosolic markers neuron-specific enolase and protein gene product 9.5. The expression of different hormones identifies specific cell types. The gut endocrine cells are reputed to be terminally differentiated and incapable of proliferation. However, some data suggest that the number of gut endocrine cells may adapt in response to tissue-specific physiological stimuli. Gut endocrine cell differentiation appears to follow a "constitutive" tissue-specific pathway, which may be disrupted and investigated by genetic manipulation in mice. It is suggested that endocrine cell homeostasis is maintained by the entry of new endocrine-committed cells along the differentiation pathway and that such intermediate cells may be sensitive to physiological stimuli as well as transforming agents.

Animals↗
PubMed1996

The importance of low blood glucose in the development of fetal sheep pancreatic endocrine cells transplanted into athymic mice.

The major problem in using fetal sheep pancreas as a transplantable source of insulin-producing cells to reverse diabetes is that beta cells do not differentiate well. Glucotoxicity is a potential explanation for this because the blood glucose level of recipient mice is higher than that of fetal sheep (7 vs. 1.5 mM). To test the effect of approximating these fetal conditions blood glucose levels of recipient athymic mice were lowered for 4 weeks from 7.3 +/- 1.6 mM to a nadir of 3.7 +/- 1.7 mM by administration of insulin pellets. This resulted in a 2.7-fold increase in the percentage of beta cells and a 5.9-fold increase in the number of glucagon-containing alpha cells. The increase in endocrine cells was probably due to improved formation from undifferentiated cells, but greater proliferation of the mature cells is also a possibility. The effect was transient with endocrine cell numbers diminishing once the effect of insulin administration ceased. It is concluded that while transplanted fetal sheep pancreas may not be suitable for reversal of diabetes, it is a useful model for studying how pancreatic endocrine cells develop.

Animals↗
PubMed1987

A preliminary study of the role of gastrointestinal endocrine cells in the maintenance of villous structure following X-irradiation.

The mechanism of gastrointestinal villous damage following ionizing irradiation is complex. Various compartments within the gastrointestinal tract have in turn been considered important for the maintenance of normal villous structure. To date, however, evidence for a single overriding regulator of epithelial well-being is lacking. In this study, the role of the gastro-intestinal (enteroendocrine) cells is explored and comparison made between endocrine cell number and villous structure. Experiments were organised using both control and irradiated groups of mice. Two time points (1 and 3 days) and three radiation doses (6, 10 and 18Gy) were employed. A simple method for endocrine cell identification and subsequent quantification is described. Endocrine cell number was then compared with villous surface detail, as seen with a scanning electron microscope (SEM). Results indicated a decrease in the endocrine cell number at all three radiation doses. Whereas at low doses endocrine cell recovery occurred between 1 and 3 days, at medium and high doses further decline was noticed. A similar pattern was seen when considering villous surface structure. It is suggested that both scanning electron microscopy and endocrine cell number provide a more sensitive indicator of gastrointestinal radiation damage than do current crypt counting techniques. In addition, a link between endocrine cell number and villous structure is proposed.

Animals↗
PubMed1977

[Pathomorphologic studies of the endocrine cells in the gastrointestinal mucosa. Physiology, cytochemistry and ultrastructure (author's transl].

With combined immunofluorescent, cytochemical and electron microscopic investigations the enterochromaffin cell system has been differentiated into 5 distinct endocrine cell types in the human stomach and into 8 cell types in the intestine. These endocrine cells are probably of neuroectodermal origin and belong to the APUD (amine precursor uptake and decarboxylation)-system. Maximal gastrointestinal hormone concentrations as determined by tissue extracts correlate fairly well to the location of each endocrine cell type in various segments of the gastrointestinal tract. In certain gastroenteropathies the pathophysiological disturbances can be explained by pathomorphological alterations of the disseminated endocrine cells. 1. The gastrin-producing G-cell is the predominating endocrine cell in the gastric antrum. Besides immunocytochemistry the G-cell can be demonstrated with argyrophilic reaction (Grimelius, 1968), masked metachromasia and leadhematoxylin. The ultrastructural features are variable, depending on functional activity. The secretory granules are usually only slightly osmiophilic, measuring 200 till 250 nm in diameter. By some working groups a positive immunofluorescence with gastrin-antisera has been demonstrated in A1- or D-cells of the pancreatic islets. However, numerous negative results have been reported, too. Considering physiological conditions, a gastrin-secretion of the human pancreatic islets has not been secured without doubt. 2. The EC-cell produces serotonin and in the intestine motilin, too. Besides the formaldehyde-induced fluorescence, these cells can be demonstrated with diazonium and argentaffin reactions, less specific with argyrophilic methods. Ultrastructurally the EC-granules are easily differeniated from the other endocrine cells by their pronounced osmiophilia and pleomorphism. In experimental conditions the EC-cells demonstrate species- and site-specific alterations. With reserpine no ultrastructural changes were demonstrable in EC-cells of the rat. However, marked ultrastructural alterations with an increase of the hormone-producing organelle system were noticed after administration of parachlorophenylalanine (PCPA) which interferes with serotonine synthesis; 5. The gastric D-cells are characterized by large secretory granules similar to pancreatic D-cells. They secrete the HCl-inhibitory peptide somatostatin. 4. The D1-cell is a cell type with unknown function. The cytoplasm contains small granules with variable electron density. According to most authors, they represent a distinct cell type and not just a variant of the G-cells. It may be very difficult, however, to separate certain forms of D1-cells from functionally altered G-cells. 5. The A-cell can be found in the gastric mucosa of certain animal species, where it has been demonstrated by immunocytochemistry with antisera to gut-glucagon. This cell type does not occur in the human gastric mucosa. 6...

Adenoma, Islet Cell↗
PubMed2002

Increased endocrine cells in treated rectal adenocarcinomas: a possible reflection of endocrine differentiation in tumor cells induced by chemotherapy and radiotherapy.

The presence of focal endocrine cells in colorectal adenocarcinoma is a relatively common phenomenon. However, endocrine differentiation in treated adenocarcinomas of the gastrointestinal tract has received little attention. We noted striking numbers of cells with endocrine morphology and phenotype in the residual tumor of six randomly encountered cases of rectal adenocarcinoma that were subjected to neoadjuvant therapy. All six cases had a substantial treatment response (> or =50%). To validate our initial observation and to explore its clinicopathologic significance, further morphologic and immunohistochemical studies were performed on 53 cases of rectal adenocarcinomas treated with preoperative radiation with (33 cases) or without (20 cases) chemotherapy. Pretreatment biopsies from 20 of the 53 cases and 79 resection specimens of rectal adenocarcinoma that received no neoadjuvant therapy were used as controls. Chromogranin positivity was identified in the posttreatment resection specimens in 36 of the 53 study cases (67.9%). Twenty of the 36 showed positive staining in > or =20% of the residual tumor cells. The chromogranin-positive cells in these cases often formed cords or nests. On hematoxylin and eosin sections these cells had markedly eosinophilic cytoplasm and round and uniform or sometimes pleomorphic nuclei with an often dense chromatin pattern. The proportion of chromogranin-positive cells was significantly associated with the extent of treatment response (p = 0.0005). Tumors treated with both chemotherapy and radiotherapy were more likely to have abundant chromogranin-positive cells compared with tumors treated with radiotherapy alone (p = 0.0004). In contrast, only 30% of the pretreatment biopsies and 17.7% of the control resection specimens of untreated rectal carcinomas showed chromogranin-positive cells, predominantly arranged as scattered individual positive cells, constituting <10% of the tumor. No significant correlation was observed between pretreatment and posttreatment specimens with regard to chromogranin positivity (p = 1.0). Ten of 15 patients (66.7%) whose resection specimens showed positive chromogranin staining failed to demonstrate any chromogranin positivity in their pretreatment biopsy specimens. In addition, groups or nests of chromogranin-positive cells noted in posttreatment specimens showed a very low Ki67 labeling index (<5%) but showed a frequency of abnormal p53 protein expression comparable with that observed in tumor foci resembling conventional adenocarcinoma (66.7% vs 62.5%). Our findings demonstrate that there is an increased frequency and density of cells with an endocrine phenotype in rectal adenocarcinomas that were subjected to neoadjuvant therapy and that the extent of endocrine cells appears proportional to the degree of treatment response. The possible mechanism for the increased endocrine cells in treated rectal adenocarcinomas may be related to induction of endocrine differentiation in tumor cells by cytotoxic insult.

Adenocarcinoma↗
PubMed1987

Gastric endocrine cell hyperplasia and carcinoid tumors in atrophic gastritis type A.

Immunohistochemical, histochemical, and morphometrical studies of six gastric carcinoid tumors and their possible precursor lesions in gastric mucosa are reported. All tumors, presenting successively at our institute, occurred in the corpus mucosa of 45- to 78-year-old patients. Two neoplasms had already metastasized. Three tumors contained gastrin- and/or serotonin-positive cells. Two groups of carcinoids, one with atrophic gastritis type A [AGA (four cases)], and one without AGA (two cases) were discerned. Only cases with AGA showed antral G cell hyperplasia consistently as well as fundic endocrine cell proliferation and sometimes multifocal tumors. This confirms previous reports that hypergastrinemia might be a predisposing condition for the development of gastric carcinoids in AGA. Fundic endocrine cell increase, verified by quantitative methods, was either diffuse or nodular. Diffuse endocrine cell hyperplasia comprised G, EC, and ECl cells. The observation that endocrine cell nodules comprised a similar mixture of endocrine cells, sometimes communicating with glands of pseudopyloric metaplasia and proving to be reversible in one case, provides evidence that these nodules are hyperplastic, but finally may lead to gastric carcinoid tumors in AGA. Size less than 150 micron, basal location, and mixed hormone content may be helpful criteria for the distinction of hyperplastic endocrine cell nodules from small carcinoid tumors.

Aged↗
PubMed1997

Endocrine cells in hepatobiliary cystadenomas and cystadenocarcinomas.

We investigated the distribution of endocrine cells in hepatobiliary cystadenoma (n = 5, two associated with mesenchymal stroma) and cystadenocarcinoma (n = 3) immunohistochemically. In normal livers (n = 20) and livers affected by hepatolithiasis (n = 15) used as controls, endocrine cells revealed by chromogranin immunostaining were located exclusively in normal or proliferating intrahepatic peribiliary glands. In the eight cases of hepatobiliary cystadenoma and cystadenocarcinoma, endocrine cells were present in four cases (50%) (1 cystadenoma, 1 cystadenoma with mesenchymal stroma, and 2 cystadenocarcinomas). Endocrine cells tended to be located beneath and among the columnar epithelial cells. Intrahepatic peribiliary glands were located in the vicinity of cystadenoma or cystadenocarcinoma in six (75%) of the eight cases, and they frequently showed cystic dilatation and contained endocrine cells. Intrahepatic peribiliary glands were located in the vicinity of the endocrine cells in all cystadenomas and cystadenocarcinomas that were positive for endocrine cells. These data show that about 50% of hepatobiliary cystadenomas and cystadenocarcinomas contain endocrine cells and suggest that hepatobiliary cystadenoma and cystadenocarcinoma may originate from intrahepatic peribiliary glands.

Aged↗
PubMed1983

The endocrine cells of the chicken proventriculus.

The endocrine cells of the chicken proventriculus were investigated by selective staining techniques, immunohistochemistry and electron microscopy. The following endocrine cell types were identified: 1) Argyrophilic ECL-cells, of unknown function, were very numerous in the 21-day-old chick, but less numerous in the newborn chick; 2) somatostatin-producing D-cells; 3) GLI-cells producing glucagon-related peptides; 4) X-cells of unknown function; 5) BN-cells producing bombesin; and 6) relatively few 5-hydroxytryptamine-producing EC-cells. Each of these cell types show a distinct morphology, distribution and histochemical reactivity. With the exception of BN-cells, they resemble rather closely the corresponding endocrine cell types previously described in the oxyntic mucosa (EGL, D, X and EC cells) or in the intestinal mucosa (L-cells) of the mammalian gut.

Animals↗
PubMed1994

Acid beta-galactosidase: a developmentally regulated marker of endocrine cell precursors in the human fetal pancreas.

Isolation of endocrine cell precursors from the human fetal pancreas will be important to the study of islet cytodifferentiation and eventually for islet transplantation in insulin-dependent diabetes. These precursor cells, from which all four islet endocrine cell types arise, are present within fetal pancreatic ductal epithelium. After enzymatic digestion and culture of the fetal pancreas, we obtained cell clusters resembling islets, but with a high content of undifferentiated cells. Histochemical staining revealed very high acid beta-galactosidase activity in over 70% of cells within the clusters. After transplantation into athymic nude mice, the islet-like cell clusters gave rise to tissue rich in differentiated endocrine cells, but low in beta-galactosidase activity. The histochemical finding of high acid beta-galactosidase activity in endocrine precursor cells was confirmed by direct measurement of lysosomal enzyme activities. In addition, we found that the expression of acid beta-galactosidase was developmentally regulated, peaking at 18-24 weeks gestation and declining to low levels in adult islets. Using a fluorogenic beta-galactosidase substrate, we were able to isolate a subpopulation of cells high in acid beta-galactosidase activity using fluorescence-activated flow cytometry. Evidence identifying these cells as potential islet cell precursors includes, besides the transplantation experiments, the colocalization in vitro of tyrosine hydroxylase, a marker of embryonic islet cells. Thus, our results indicate that high acid beta-galactosidase activity serves as a marker for a population of fetal pancreatic cells with the potential to differentiate and grow into mature pancreatic endocrine cells.

Biomarkers↗
PubMed1987

A mixed pattern of endocrine cells in metaplastic Barrett's oesophagus. Evidence that the epithelium derives from a pluripotential stem cell.

In order to characterize the differentiation of endocrine cells present in Barrett's oesophagus and to determine if they express a single or multiple hormonal pattern, endoscopic biopsies were taken from both the lesion and the fundus of 45 patients and studied at the light microscopical level. Conventional histology revealed three different epithelial patterns: gastric atrophic fundic, intestinal and junctional. A mixture of these patterns was present in 28 cases (62%) and the single type was identified in 17 cases (38%). The use of three silver staining methods and antibodies to human chromogranins allowed us to identify numerous endocrine cells in all but 1 case. Eleven sera against all the most common hormones stored in the endocrine cells of the gut were used to identify the main products of the cells. The following immunoreactivities were identified: 5-hydroxytryptamine (5-HT) (in 75% of the studied cases), somatostatin (87%), motilin (31%), pancreatic polypeptide (PP) (20%), glucose-dependent insulinotropic polypeptide (20%), gastrin (15%), glucagon (15%), peptide tyrosine tyrosine (13%), secretin (7%) and neurotensin (2%). No cholecystokinin-immunoreactive cells were identified. Our results indicated that, in Barrett's epithelium, both gastric and intestinal endocrine cells differentiate, in accordance with the variability of differentiation in the non-endocrine cells present in the different types of columnar epithelium. These findings provide support for the conclusion that Barrett's epithelium arises from a pluripotential stem cell capable of both gastric and intestinal differentiation.

Aged↗
PubMed1996

Gastric endocrine cells: gene expression, processing, and targeting of active products.

Endocrine cells of the gastric epithelium secrete biologically active peptides and small messenger molecules such as histamine, serotonin, and gamma-aminobutyric acid. The secretory products may act locally (paracrine or autocrine effects) or at distant targets after delivery in the circulation (hormonal effects). the contents of the gastric lumen control both secretion of gastric endocrine cells and the expression of genes involved in the synthesis of their active secretory products; in some cases, gene regulation may occur over periods as short as that required for digestion of a single meal. The conversion of inactive peptide precursors to their active forms takes place during transit along the secretory pathway and is only completed after sequestration in secretory granules. the processing of the gastrin precursor provides a useful model for studying prohormone processing. Generation of the well-known amidated gastrins requires prohormone cleavage and COOH-terminal amidation; the products stimulate acid secretion and mucosal growth. However, recent work indicates that biosynthetic intermediates that do not stimulate acid secretion may nevertheless act at a novel receptor to stimulate growth, so that control of prohormone processing determines which of two alternative types of biologically active peptide is released by gastrin cells. Gastric endocrine cells also have the capacity to accumulate small messenger molecules in secretory vesicles, via proton exchangers. Recent work indicates physiological regulation of the expression of genes encoding cytosolic enzymes such as histidine decarboxylase, which converts histidine to histamine, and of secretory granule transporters such as vesicular monoamine transporter type 2, which concentrates amines in secretory vesicles. Together these findings suggest that modulation of regulatory peptide and amine biosynthesis in gastric endocrine cells constitutes a primary response of the stomach to the arrival of a meal.

Amino Acid Sequence↗
PubMedDate not supplied

Abnormalities of small intestinal endocrine cells in non-obese diabetic mice.

The endocrine cells in the duodenum of pre-diabetic and diabetic female non-obese diabetic (NOD) mice aged 22-24 weeks were studied by means of immunohistochemistry and computed image analysis as well as by radioimmunoassays of tissue extracts. As controls, 12 female BALB/cJ mice of the same age as NOD mice were used. The number of secretin-immunoreactive cells increased in diabetic but not in pre-diabetic NOD mice. The level of extractable secretin was higher in both pre-diabetic and diabetic NOD mice. The number of GIP-, CCK/gastrin-, and serotonin-immunoreactive cells was significantly reduced in both pre-diabetic and diabetic NOD mice. There was no statistical difference in the number of somatostatin-immunoreactive cells between the NOD mice and controls. The level of GIP was higher and gastrin was lower in NOD mice compared to controls. There was no statistical difference in the somatostatin level between the NOD mice and controls. The cell secretory index was elevated in all the endocrine cell types except CCK/gastrin cells. It has been suggested that some of the changes in the duodenal endocrine cells could be attributed to the diabetes state, but most of the changes seem to take place before the onset of diabetes. The abnormalities in the duodenal endocrine cells observed here in an animal model for diabetes type I might have relevance for the gastrointestinal dysfunction displayed in human diabetes.

Animals↗
PubMed2001

Isolation, culture, and characterization of endocrine cells from 6-month-old porcine pancreas.

Porcine endocrine cells were isolated from pancreas of 6-month-old pigs by two-step enzymatic digestion procedures. They were separated by the density gradient (isopycnic) centrifugation method using Histopaque-1077. Isolated cells were cultured and divided into two groups: suspension cells and adhesion cells. Suspension cells maintained their cell numbers on and after 7 days in culture. Approximately 1 x 10(7) cells were obtained from single pancreas of a 6-month-old pig. The cultured suspension cells took up dithizone (DTZ) staining 14 days after isolation in culture and indicated the presence of beta-cells. In in vitro study, the suspension cells were capable of secreting insulin into the culture medium. The suspension cells were tested for insulin and glucagon staining by Western blot analysis. These results indicated the maintenance of endocrine cell function after isolation. However, cultured adhesion cells failed to maintain their function during culture. In in vivo study, the suspension cells were transplanted into diabetes-induced nude mice. Reduction in blood glucose level was obtained after transplantation. Intraperitoneal glucose tolerance test (IPGTT) results showed a normal pattern of blood glucose clearance. After 1 week, the transplanted endocrine cells were detected with anti-insulin antibody by immunostaining and it showed the presence of viable beta-cells under the renal capsule of nude mice. Collectively, our results suggest that isolated and cultured suspension porcine endocrine cells maintained their endocrine function. These endocrine cells can be used as isolated islets for further study, including transplantation experiments.

Animals↗
PubMed1984

Immunocytochemical study of the gastroenteropancreatic endocrine cells of the sheep.

The gastroenteropancreatic (GEP) endocrine cells of the sheep were studied immunocytochemically and their distribution and frequency were determined. Eleven types of endocrine cells were revealed. In the abomasum, somatostatin-, gastrin-, glucagon- and glicentin-immunoreactive cells were detected with the highest frequency in the pyloric region. In the small intestine, somatostatin-, gastrin-, CCK-, motilin-, neurotensin-, secretin-, substance P-, glucagon-, glicentin- and BPP-immunoreactive cells were found and were most numerous in the duodenum except for neurotensin-, glucagon- and glicentin-immunoreactive cells which were more concentrated in the ileum. In the large intestine, somatostatin-, substance P-, glucagon-, glicentin- and BPP-immunoreactive cells were localized with the last three cell types being more concentrated in the rectum. In the pancreas, somatostatin-, glucagon-, glicentin-, BPP- and insulin-immunoreactive cells predominated within the islets and were also scattered in the exocrine portion and rarely detected in duct epithelial cells. The differences between the distribution and frequency of the GEP endocrine cells of the sheep and those of monogastric species are discussed.

Animals↗