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PubMed1989

Endocrine cell carcinoma (carcinoid) of the gallbladder.

We report two cases of endocrine cell carcinoma of the gallbladder associated with adenocarcinoma. The patients were women with numerous gallstones. Histologically, the tumors consisted of adenocarcinoma and endocrine cell carcinoma. An apparent transition was noted between the two types. Tumor cells of both the endocrine cell carcinoma and the adenocarcinoma were argyrophilic. In one case the tumor was surrounded by metaplastic mucosa; in the other case, it was surrounded by dysplastic and metaplastic mucosa. The nonneoplastic mucosae also contained argyrophil cells in varying number. These findings suggest that endocrine cell carcinoma of the gallbladder is derived from metaplastic epithelium of the gallbladder.

Adenocarcinoma↗
PubMed1996

Processing of mutated human proinsulin to mature insulin in the non-endocrine cell line, CHO.

Heterologous genes encoding proproteins, including proinsulin, generally produce mature protein when expressed in endocrine cells while unprocessed or partially processed protein is produced in non-endocrine cells. Proproteins, which are normally processed in the regulated pathway restricted to endocrine cells, do not always contain the recognition sequence for cleavage by furin, the endoprotease specific to the constitutive pathway, the principal protein processing pathway in non-endocrine cells. Human proinsulin consists of B-Chain-C-peptide-A-Chain and cleavage at the B/C and C/A junctions is required for processing. The B/C, but not the C/A junction, is recognised and cleaved in the constitute pathway. We expressed a human proinsulin and a mutated proinsulin gene with an engineered furin recognition sequence at the C/A junction and compared the processing efficiency of the mutant and native proinsulin in Chinese Hamster Ovary cells. The processing efficiency of the mutant proinsulin was 56% relative to 0.7% for native proinsulin. However, despite similar levels of mRNA being expressed in both cell lines, the absolute levels of immunoreactive insulin, normalized against mRNA levels, were 18-fold lower in the mutant proinsulin-expressing cells. As a result, there was only a marginal increase in absolute levels of insulin produced by these cells. This unexpected finding may result from preferential degradation of insulin in non-endocrine cells which lack the protection offered by the secretory granules found in endocrine cells.

Animals↗
PubMed1989

Chromogranin A (CgA) in the gastro-entero-pancreatic (GEP) endocrine system. II. CgA in mammalian entero-endocrine cells.

Chromogranin A (CgA) and related acidic proteins are widely distributed in the organism. They are also present in entero-endocrine cells and in other members of the paraneuron family. Therefore, CgA has been claimed as an universal marker of this cellular community. To yield precise data about the distribution of CgA in entero-endocrine cells, all segments of the gastro-intestinal tract of five mammalian species (man, cattle, pig, cat, guinea-pig) were investigated immunohistochemically for CgA. In serial semithin plastic sections, all CgA-immunoreactive endocrine cells were identified for resident amines or peptides. CgA could be found in ten hormonally identified endocrine cell types and in two or three other endocrine cell types. Entero-endocrine cells containing amines (histamine, serotonin) regularly exhibited CgA-immunoreactivities. In contrast, peptide-containing endocrine cells were largely heterogeneous: Their CgA-immunoreactivities varies among the species, among the gastro-intestinal segments, and even among the members of the same cell population. Hence, seen histochemically, CgA is no universal marker for entero-endocrine cells. Seen biochemically, the observed heterogeneities of CgA-immunoreactivities theoretically can be attributed to various factors (species-specificities of CgA, subclasses of chromogranins, processing of CgA or its pro-protein). Most probably, these heterogeneities are caused by species- or cell-specific differences in the extent of processing of CgA. In addition, some findings point to certain interrelations between the processing or storage of CgA and resident peptides in the secretion granules of enteroendocrine cells.

Animals↗
PubMed1991

Chemical coding of endocrine cells of the airways: presence of helodermin-like peptides.

The epithelium of the airways is rich in endocrine cells containing serotonin and/or a wide variety of regulatory peptides. These cells usually occur in clusters in the lungs but are also found scattered in the larynx and trachea. In the present study, endocrine cells in the airways of mouse, rat, hamster, guinea pig, pig, sheep and squirrel monkey were examined for the presence of serotonin, helodermin-like peptides and other regulatory peptides using immunocytochemistry and radioimmunoassay. In addition, we looked for the protein gene product 9.5 (PGP), which occurs in many peptide hormone-producing endocrine cells in the body. Both clustered and scattered endocrine cells in the airways were found to display coexistence of serotonin and peptides, such as a helodermin-like peptide, calcitonin and calcitonin gene-related peptide (CGRP). The PGP-immunoreactive cells were numerous and included elements containing serotonin and/or regulatory peptides. An additional PGP-immunoreactive endocrine cell population lacked serotonin and regulatory peptides. Helodermin-immunoreactive material was demonstrated in endocrine cells of the airways in the mouse and hamster but not in any of the other species studied. Serotonin was an endocrine cell constituent in all the species studied. Calcitonin and CGRP could be demonstrated by immunocytochemistry in the mouse, rat, and hamster, but not in the guinea pig, sheep, pig and monkey.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Dissociation of epithelial cells from rabbit trachea and small intestine with demonstration of APUD endocrine cells.

In this study the entire epithelial lining of tracheas and a 15-cm segments of small intestine were dissociated into individual cell components after 45-minute incubation with 1% pronase. Light and electron microscopy of isolated cells confirmed good morphologic preservation of various epithelial cell types dissociated from the trachea and small intestinal mucosa. Of particular interest was the recovery and preservation of APUD endocrine cells, which are known to be widely dispersed amongst various non-endocrine epithelial cells in both the trachea and small intestine. The APUD cells were demonstrated in dissociated cell preparations by a formaldehyde-induced fluorescence method, Grimelius' silver nitrate stain, and electron microscopy. The isolated APUD cells retained their characteristic features, e.g., amine-handling properties, argyrophilia and cytoplasmic dense-core vesicles. The cell dissociation method described in this report provides high yields of viable epithelial cells in single cell suspensions which are suitable for further cell separation into homogeneous populations of single kinds of cells, including the APUD endocrine cells. Availability of methods for isolation of tracheal and intestinal APUD cells will facilitate further studies, in vitro, on secretory, metabolic and functional aspects of these cells.

Amines↗
PubMed1988

Increased intracellular levels of calcitonin gene-related peptide-like immunoreactivity in pulmonary endocrine cells of hypoxic rats.

The mammalian respiratory tract contains innervated groups of endocrine cells which are believed to respond to hypoxia. We have demonstrated the involvement of a specific regulatory peptide produced by the cells, calcitonin gene-related peptide (CGRP), in this response. Cells immunoreactive for CGRP or for protein gene product 9.5 (PGP 9.5), a general marker of nerves and endocrine cells, were quantified in sections of lungs from hypoxic (21 days, 10 per cent O2) and normoxic rats. An immunostaining method employing supra-optimal dilutions of primary antiserum was used. This detects variations in antigen concentration which may be masked if the routine, optimal dilution is used. The number of CGRP-immunoreactive endocrine cells was significantly (P less than 0.001) greater in the lungs of hypoxic rats (76.9 +/- 10.1 cells/cm2, mean +/- SEM) compared with controls (19.7 +/- 2.4). However, the numbers of PGP 9.5-immunoreactive cells were the same in both groups (81.3 +/- 12.2, hypoxic; 79.5 +/- 9.8 control), suggesting that the total number of endocrine cells did not change. It is concluded therefore that the apparent increase in CGRP-immunoreactive endocrine cells in hypoxic rat lungs is due to increased intracellular levels of the peptide. Since CGRP is a vasodilator, this could have important implications in the vasoconstrictor response to hypoxia.

APUD Cells↗
PubMed1984

Calcitonin as a marker for diethylnitrosamine-induced pulmonary endocrine cell hyperplasia in hamsters.

Immunoreactive calcitonin (iCT) has been localized in solitary endocrine cells and in clusters of these cells, called neuroepithelial bodies, in human and hamster lungs. It has been demonstrated that hyperplasia of hamster lung endocrine cells occurs following exposure to diethylnitrosamine (DEN), a systemic carcinogen. In the present study we have investigated iCT as a hormonal correlate of DEN-induced pulmonary endocrine cell hyperplasia in hamsters. Hamsters were given 3 mg of DEN per animal, subcutaneously, twice a week and then serially sacrificed at 2, 4, 8, and 12 weeks. By immunocytochemistry, iCT-containing cells could be demonstrated in thyroids, tracheal glands, and throughout the airway epithelium. At 8 or 12 weeks of DEN exposure, one to eight neuroepithelial bodies with iCT-containing cells were identified per square centimeter of lung sections, in contrast to zero to one neuroepithelial bodies/cm2 in control hamsters. By radioimmunoassay, pulmonary iCT increased significantly at 8 weeks of DEN exposure, amounting to 3.5-fold the control values at 12 weeks. Serum iCT increased at 4 weeks of exposure and by 12 weeks had tripled (183 +/- 62 pg/ml, mean +/- SD, p less than 0.001), as compared with control animals. Subsequently, DEN was stopped for 4 weeks, and the levels of both serum and lung iCT decreased, although they remained higher than those of controls. The serum and lung iCT of control hamsters was constant throughout the experiment (49 +/- 26 pg/ml and 1754 +/- 489 pg/gm of wet weight, mean +/- SD, respectively). Thyroidal iCT levels of exposed hamsters did not differ from those of the controls; both increased progressively. The DEN-exposed animals had retarded growth as compared with the controls. Column chromatography using superfine Sephadex G-75 demonstrated that both DEN-exposed and control lungs contained iCT with a predominant molecular size corresponding to the dimer of synthetic human calcitonin; whereas thyroidal iCT was mostly monomeric (approximately 3,500 daltons). The increase of pulmonary iCT correlates well with the 4-fold increase of pulmonary endocrine cells, reported earlier following similar DEN exposure. We conclude that iCT levels of hamster sera and lungs can be used as a biochemical parameter to monitor hyperplasia of the pulmonary endocrine cells in these animals.

Animals↗
PubMed1999

Intestinal endocrine cells in myotonic dystrophy: an immunocytochemical and computed image analytical study.

OBJECTIVES: To study intestinal endocrine cell types in patients suffering from myotonic dystrophy (MD) and diarrhoea. DESIGN: Comparative study between MD patients and matched controls. SETTING: Departments of Medicine, Central Hospital, Boden, and University Hospital, Umeå, Sweden. SUBJECTS: Ten patients with MD (four males and six females) and suffering from diarrhoea. Ten healthy volunteers served as controls for the duodenal study and 13 patients under investigation for rectal bleeding and with endoscopically normal mucosa were controls for the rectal study. MEASUREMENTS: The duodenal and rectal endocrine cell types were identified by immunohistochemical investigation and quantified by computed image analysis. RESULTS: The total endocrine cell area in the duodenum as demonstrated by chromogranin A-immunoreactivity was significantly increased in MD as compared with the controls (126 +/- 58 vs. 48 +/- 22 x 10(3) microns 2 mm-2 in crypts and 230 +/- 183 vs. 28 +/- 22 in villi, respectively, P < 0.01). The increase included all types of endocrine cells studied, namely those positive for serotonin, cholecystokinin (CCK)/gastrin, secretin, gastric inhibitory peptide (GIP) and somatostatin. In the rectum, the total endocrine cell area as determined by chromogranin A-immunoreactivity was also significantly increased, but there was no statistical difference between the controls and patients with respect to the area of serotonin-, peptide YY (PYY)-, pancreatic polypeptide (PP)- or somatostatin-immunoreactive cells. CONCLUSIONS: The increase in endocrine cell area indicates a disturbed endocrine regulation of the gastrointestinal tract that may contribute to the development of gastrointestinal symptoms encountered in MD patients.

Adult↗
PubMed1999

Intestinal endocrine cells in myotonic dystrophy: an immunocytochemical and computed image analytical study.

OBJECTIVES: To study intestinal endocrine cell types in patients suffering from myotonic dystrophy (MD) and diarrhoea. DESIGN: Comparative study between MD patients and matched controls. SETTING: Departments of Medicine, Central Hospital, Boden, and University Hospital, Umeå, Sweden. SUBJECTS: Ten patients with MD (four males and six females) and suffering from diarrhoea. Ten healthy volunteers served as controls for the duodenal study and 13 patients under investigation for rectal bleeding and with endoscopically normal mucosa were controls for the rectal study. MEASUREMENTS: The duodenal and rectal endocrine cell types were identified by immunohistochemical investigation and quantified by computed image analysis. RESULTS: The total endocrine cell area in the duodenum as demonstrated by chromogranin A-immunoreactivity was significantly increased in MD as compared with the controls (126 +/- 58 vs. 48 +/- 22 x 10(3) micron 2 mm-2 in crypts and 230 +/- 183 vs. 28 +/- 22 in villi, respectively, P < 0.01). The increase included all types of endocrine cells studied, namely those positive for serotonin, cholecystokinin (CCK)/gastrin, secretin, gastric inhibitory peptide (GIP) and somatostatin. In the rectum, the total endocrine cell area as determined by chromogranin A-immunoreactivity was also significantly increased, but there was no statistical difference between the controls and patients with respect to the area of serotonin-, peptide YY (PYY)-, pancreatic polypeptide (PP)- or somatostatin-immunoreactive cells. CONCLUSIONS: The increase in endocrine cell area indicates a disturbed endocrine regulation of the gastrointestinal tract that may contribute to the development of gastrointestinal symptoms encountered in MD patients.

Adult↗
PubMed1985

Endocrine cells in the female genital tract.

Endocrine cells are normal inhabitants of the para-urethral, Bartholin's and endocervical glands and of mesonephric rests. All these cells were characterized as serotonin-storing cells. In the para-urethral and Bartholin's glands, serotonin-containing cells were most often found in the transitional epithelium of excretory ducts. Endocrine cells participated in some pathological conditions. Abundant argentaffin cells were observed among the terminal ductules in chronic bartholinitis and serotonin-storing cells were identified in a peculiar ectocervical epithelium. Numerous serotonin-storing cells were detected in a well-differentiated adenocarcinoma of cervix occurring in a patient with the Peutz-Jeghers syndrome. Argyrophilic cells were present in cases of endometrial carcinomas; a striking feature was the demonstration of gut peptide hormones in an unusual type of endometrial adenocarcinoma. Finally, serotonin-storing cells were a constituent of Brenner tumours. It is suggested that a similar endocrine pattern may be shared by tissues originating from both Müllerian ducts and the urogenital sinus.

Bartholin's Glands↗
PubMed1997

Intestinal-type fibroblasts selectively influence proliferation rate and peptide synthesis in the murine entero-endocrine cell line STC-1.

The intestinal epithelium consists of enterocytes, endocrine cells, goblet cells and Paneth cells, which differentiate from pluripotent stem cells located at the crypt bases. The role of the epithelial-mesenchymal inter-actions has been well documented for the differentiation of enterocytes, but the mechanisms that control endocrine cell differentiation are poorly understood. We have cultured the intestinal endocrine cell line STC-1, which synthesizes most of the intestinal peptide hormones, in media conditioned by several subepithelial fibroblast cell lines from three distinct sites of intestine. The fibroblast Swiss 3T3 cell line was used as a non-intestinal control. Our results show that culture media from intestinal fibroblasts inhibit the proliferation rate of STC-1 cells, while those from Swiss 3T3 fibroblasts do not. As regards peptide hormone gene expression, Swiss 3T3-conditioned media have no effect, whereas media from intestinal fibroblasts variably affect cholecystokinin, glucagon, secretin and somatostatin mRNA levels. In particular, clonal subepithelial myofibroblasts do not exert the same effects as mixed subepithelial fibroblasts from homologous intestinal segment. Taken together, these results suggest that cultured fibroblasts of intestinal origin release soluble factors that inhibit STC-1 cell proliferation and modulate, in a region-specific manner, the expression of hormonal peptide genes in this nonspecialized endocrine cell line.

Animals↗
PubMed1991

Topology of chromogranins in secretory granules of endocrine cells.

Chromogranins A and B are glycoproteins originally detected in the adrenal medulla. These proteins are also present in a variety of neuroendocrine cells. The subcellular distribution of the chromogranins, and particularly their intra-granular topology are of special interest with respect to their putative functions. Endocrine cells of the guinea pig adrenal medulla, pancreas and gastric mucosa were investigated immunoelectron microscopically for the subcellular distribution of both chromogranins. Out of 13 established endocrine cell types in all locations, only two endocrine cell types showed immunoreactivity for both chromogranin A and B, and eight endocrine cell types showed immunoreactivities only for chromogranin A. These immunoreactivities varied inter-cellularly. Three endocrine cell types were unreactive for the chromogranins. Moreover, some hormonally non-identified endocrine cells in the pancreas and the gastric mucosa also contained chromogranin A immunoreactivities. Subcellularly, chromogranin A or B were confined to secretory granules. In most endocrine cells, the secretory granules showed chromogranin immunoreactivities of varying densities. Furthermore, the intra-granular topology of chromogranin A or B in the secretory granules varied considerably: in some endocrine cell types, i.e. chromaffin-, gastrin- and enterochromaffin-like-cells, chromogranin A immunoreactivity was localized in the perigranular and/or dense core region of the secretory granules; in others, i.e. insulin-, pancreatic polypeptide- and bovine adrenal medulla dodecapeptide-cells, it was present preferentially in the electron-opaque centre of the secretory granules; chromogranin B immunoreactivity was localized preferentially in the perigranular region of the secretory granules of chromaffin cells and gastrin-cells. The inter-cellular and inter-granular variations of chromogranin A and B immunoreactivities point to differences in biosynthesis or processing of the chromogranins among endocrine cells and their secretory granules.

Adrenal Medulla↗
PubMed1996

Cell-to-cell communication in the anterior pituitary: evidence for gap junction-mediated exchanges between endocrine cells and folliculostellate cells.

The ability of rat anterior pituitary cells to communicate through gap junctions (GJ) was studied using a fluorescent molecule, Lucifer Yellow (LY), which freely passes through GJ channels. The probe was introduced into the cell cytoplasm by using either the cut-end loading method on intact tissue, or cell microinjection on cultured cells. The identification of communicating cells was performed by immunofluorescence labeling of specific hormones in endocrine cells and of S100 protein in folliculostellate (FS) cells. Rat anterior pituitary cells in their physiological organization, i.e. in the intact tissue, exhibited a high level of coupling through GJ. LY-labeled cells were found up to 300-microns apart from its site of introduction. The communicating cells were primarily PRL cells, GH cells, and FS cells. Only a few LH, TSH, and ACTH cells were labeled with LY. Anterior pituitary cells, isolated from the rat tissue by mild protease treatment and cultured for 3 days, reestablished functional GJ as demonstrated by microinjection of LY into individual cells. By immunolabeling of specific hormones and/or S100 protein, we found a GJ coupling between FS cells, and between FS cells and endocrine cells, including PRL cells. The communication between FS cells was by far the most frequent. In conclusion, we demonstrate the presence of functional GJ between anterior pituitary cells of the same type and between anterior pituitary cells having distinct differentiated functions.

Animals↗
PubMedDate not supplied

Immunohistochemical aspects of chromogranins in endocrine cells of the duodenal mucosa in some primates.

Endocrine cells in the duodenal mucosa of some primates (Cercopithecus aetiops, Macaca cinomolgus-nemestrina and Macaca rhesus) have been studied with immunohistochemical methods for chromogranins. Material sampling immediately after death (by carotid bleeding concomitantly with formalin 10% perfusion) was helpful in the study of endocrine cells. The location and number of endocrine cells of the duodenal mucosa of the primates under study are generally similar to those of humans. The use of an antibody cocktail against all three Cgs/Sgs appears to be the method of choice to identify neuroendocrine granule-containing cells. When comparing the results of this study with those obtained by us in a previous work by silver staining, the Grimelius technique is recommended together with the immunohistochemical techniques for chromogranins in the practice of the usual diagnosis of the endocrine pathology.

Animals↗
PubMed1983

Pathology of endocrine cells in gastric mucosa.

Pathological changes of gastric endocrine cells are reviewed. The lesions are subdivided according to the type of mucosa in which they originate. Hyperplasias of fundic endocrine cells, probably related to the patient's concomitant hypergastrinemia, were found in Zollinger Ellison syndrome and in chronic atrophic gastritis. They may evolve into carcinoid tumors. Typical and atypical forms of fundic carcinoids have been described, usually without specific clinical syndrome. Antral gastrin G cells proliferate in achlorhydric, hypergastrinemia patients while their involvement in peptic ulcer disease is probably limited to a minority of cases. Antral gastrin secreting tumors are rare. Metaplasic intestinal epithelium also harbors endocrine cells that may present hyperplastic and neoplastic changes.

Endocrine Glands↗
PubMed1982

Neuron specific enolase (NSE) immunostaining detection of endocrine cell hyperplasia in adult rats exposed to asbestos.

Hyperplasia of endocrine cells in the lung of the adult rat exposed to asbestos has only been characterised so far by electron microscopy as there is a lack of reliable staining techniques for their demonstration at light microscopical level. Neuron specific enolase (NSE), an isoenzyme of the glycolytic enzyme enolase has recently been shown to be present in lung endocrine cells. In this study we reveal a marked endocrine cell hyperplasia at light microscopical level in the lungs of adult rats exposed to asbestos using antibodies to NSE. Very large groups of NSE-immunoreactive cells (20-80) were only observed in the lungs of rats exposed to asbestos for 12 months. In addition smaller groups of cells (2-10) known to be present normally and to decrease with age, were rarely noted in the controls but were frequently detected in the treated rats. Immunoreactive NSE is therefore a very good marker for endocrine cell hyperplasia and thus of early neoplastic changes.

Animals↗
PubMed1995

Characterization of promoter elements required for cell-specific expression of the neurotensin/neuromedin N gene in a human endocrine cell line.

Expression of the gene encoding neurotensin/neuromedin N (NT/N) is mostly limited to the brain and specialized enteroendocrine cells (N cells) of the distal small intestine. We have analyzed the NT/N DNA sequences upstream of the RNA start site that direct cell-specific expression using a novel human endocrine cell line, BON, that resembles intestinal N cells in several important aspects, including NT/N precursor protein processing, ratios of different NT/N mRNA forms, and high levels of constitutive expression of the NT/N gene. Transient transfection assays with plasmids with progressive 5' deletions of the rat NT/N promoter identified the proximal 216 bp of 5' flanking sequences as essential for high-level constitutive NT/N expression in BON cells. In addition, a detailed mutational analysis defined multiple regions within the proximal 216 bp that contribute to cell-specific NT/N expression. These elements include a proximal cyclic AMP response element (CRE)/AP-1-like motif (TGACATCA) that binds c-Jun, JunD, CRE-binding (CREB), and ATF proteins, a near-consensus glucocorticoid response element, and a distal consensus AP-1 site that binds c-Fos, Fra-1, and JunD. In addition, elements contained within two 21-bp imperfect direct repeats play an important role in NT/N expression in BON cells and may bind novel factors that act as positive regulators of NT/N expression. DNase I footprinting and gel shift analyses demonstrate that the sites identified by mutational analysis, and at least one additional site, specifically bind BON cell nuclear proteins in vitro. We speculate that a complex pattern of regulation requiring interaction between a proximal CRE/AP-1-like motif and other upstream control elements play an important role in the high-level constitutive expression of NT/N in the human endocrine cell line BON. In addition, the BON cell line provides a unique model to further characterize the factors regulating cell-specific NT/N expression and to better understand the mechanisms responsible for the terminal differentiation of the N-cell lineage in the gut.

Activating Transcription Factor 1↗
PubMed2005

Immunohistochemical study on gastrointestinal endocrine cells of four reptiles.

AIM: To clarify the types, regional distributions and distribution densities as well as morphological features of gastrointestinal (GI) endocrine cells in various parts of the gastrointestinal track (GIT) of four reptiles, Gekko japonicus, Eumeces chinensis, Sphenomorphus indicus and Eumeces elegans. METHODS: Paraffin-embedded sections (5 mum) of seven parts (cardia, fundus, pylorus, duodenum, jejunum, ileum, rectum) of GIT dissected from the four reptiles were prepared. GI endocrine cells were revealed by using immunohistochemical techniques of streptavidin-peroxidase (S-P) method. Seven types of antisera against 5-hydroxy-tryptamine (5-HT), somatostatin (SS), gastrin (GAS), glucagon (GLU), substance P (SP), insulin and pancreatic polypeptide were identified and then GI endocrine cells were photomicrographed and counted. RESULTS: The GI endocrine system of four reptiles was a complex structure containing many endocrine cell types similar in morphology to those found in higher vertebrates. Five types of GI endocrine cells, namely 5-HT, SS, GAS, SP and GLU immunoreactive (IR) cells were identified in the GIT of G. japonicus, E. chinensis and S. indicus; while in the GIT of E. elegans only the former three types of endocrine cells were observed. No PP- and INS- IR cells were found in all four reptiles. 5-HT-IR cells, which were most commonly found in the pylorus or duodenum, distributed throughout the whole GIT of four reptiles. However, their distribution patterns varied from each other. SS-IR cells, which were mainly found in the stomach especially in the pylorus and/or fundus, were demonstrated in the whole GIT of E. chinensis, only showed restricted distribution in the other three species. GAS-IR cells, with a much restricted distribution, were mainly demonstrated in the pylorus and/or the proximal small intestine of four reptiles. GLU-IR cells exhibited a limited and species-dependent variant distribution in the GIT of four reptiles. SP-IR cells were found throughout the GIT except for jejunum in E. elegans and showed a restricted distribution in the GIT of G. japonicus and S. indicus. In the GIT of four reptiles the region with the highest degree of cell type heterogeneity was pylorus and most types of GI endocrine cells along the GIT showed the peak density in pylorus as well. CONCLUSION: Some common and unique features of the distribution and morphology of different types of GI endocrine cells are found in four reptiles. This common trait may reflect the similarity in digestive physiology of various vertebrates.

Animals↗