Structure and cytophysiology of gastric endocrine gland cells after repeated administration of testosterone propionate

By means of light, electron microscopy and morphometry methods contents and structural organization of endocrinocytes have been investigated in gastric glands of rats, to whom testosterone propionate has been injected for 5, 10, 15, 20 days. The hormone produces certain stimulating effect on the endocrine apparatus function. During the first stages of the experiment most of the endocrinocytes are at the state of active secretion; this is testified as a decreasing composition of histochemically revealed cells in epithelium and their degranulation. During the following stages the process of synthesis is activated in the cells and their amount increases. Appearance of numerous agranular, poorly differentiated endocrinocytes and exo-endocrine cells demonstrates certain intensification of cytogenesis of endocrinocytes in the gastric epithelium. The changes observed are considered as adaptive, directed to stabilize homeostasis, when the hormonal balance is disturbed.     

Histamine in endocrine cells in the stomach. A survey of several species using a panel of histamine antibodies

Antibodies to histamine were used to examine the localization of the amine in cells of the stomach and upper small intestine of a great variety of species, including cartilaginous and bony fish, amphibia, reptiles (lizard), birds (chicken) and a large number of mammals. In all species gastric histamine was localized in endocrine cells (invariably found in the epithelium) and mast cells (usually with an extra-epithelial localization). The endocrine cells were identified as such by immunostaining with antibodies to chromogranin A and the mast cells were identified by toluidine blue staining. Histamine-immunoreactive endocrine cells were found almost exclusively in the acid-producing part of the stomach; only rarely were such cells observed in the pyloric gland area. They were fairly numerous in the gastric mucosa of the two subclasses of fish as well as in the amphibia and reptile species studied. Here, the majority of the histamine-immunoreactive endocrine cells seemed to have contact with the gastric lumen (open type cells) and were located in the surface epithelium (certain fish only) or together with mucous neck cells at the bottom of the pits. In the chicken, histamine-immunoreactive endocrine cells were numerous and located peripherally in the deep compound glands. They were without contact with the lumen (closed type) and had long basal extensions ("paracrine" appearance), running close to the base of the oxyntic-peptic cells. In mammals, the number of histamine-immunoreactive endocrine cells in the stomach varied greatly. They were particularly numerous in the rat and notably few in the dog, monkey and man. In all mammals, the histamine-immunoreactive endocrine cells were of the closed type and located basally in the oxyntic glands. They often had a "paracrine" appearance with long basal processes. Histamine-storing mast cells, finally, were few in both subclasses of fish as well as in the amphibian species and in the lizard. They were fairly numerous in chicken proventriculus (beneath the surface epithelium), few in the oxyntic mucosa of mouse, rat and hamster, moderate in number in hedgehog, guinea-pig, rabbit, pig and monkey, and numerous in cat, dog and man.(ABSTRACT TRUNCATED AT 400 WORDS)     

Endocrine cells of stomach epithelium in the ontogenesis of albino rats

By means of the light and electron microscopy methods structural bases of differentiation and contents of endocrine cells of the stomach epithelium have been studied during the white rat pre- and postnatal development. The development of the endocrine epithelial cells occurs in parallel with the exocrinic ones. Endocrine EC-, G-, D-, P-cells are the first to be revealed in composition of the embryonal stomach epithelium, the others--during the early postembryonic period. The differentiation of the endocrine cells is characterized with asynchronism, is accompanied with a gradual development of organells, increasing amount of secretory granules and appearance of polarity in their distribution. By the 30th day of the postnatal development, the amount of the endocrine cells in the stomach epithelium increases by 5 times in comparison to those in the 1-day-old animals, with simultaneous reaching of the high level in specific differentiation.     

Endocrine cells in the cardial glands of the esophagus in man

Distribution of endocrine cells in composition of the secretory epithelium of the cardial glands of the human esophagus in both sex and at various age has been investigated. In spiral paraffin slices the endocrine cells have been revealed by means of different silver impregnation methods (after Grimelius, Masson--Hamperl, Sevier--Munger), Sevke technique, ferry-ferrocyanide method. Some cells have been revealed, which according to the specific signs of their granule staining resemble very much G-, EC-, ECL-cells of the stomach. They can be triangular, flatten or polygonal and are stained in the cardial gland epithelium as single diffuse cells, or as groups of cells. Staining of the slices with aldehyde-fuchsin in various modifications reveals dark cells with dark-violet granules and lighter cells with acidophilic granules. Sometimes among these cells certain cells with light-violet cytoplasm are revealed. All these cells can be arranged both in composition of the secretory epithelium of the glands and in conglomerates of cells, resembling pancreatic islands. According to their tinctorial properties they resemble A-, B-, D-cells of these islands.     

Histamine in endocrine cells in the stomach

Summary Antibodies to histamine were used to examine the localization of the amine in cells of the stomach and upper small intestine of a great variety of species, including cartilaginous and bony fish, amphibia, reptiles (lizard), birds (chicken) and a large number of mammals. In all species gastric histamine was localized in endocrine cells (invariably found in the epithelium) and mast cells (usually with an extra-epithelial localization). The endocrine cells were identified as such by immunostaining with antibodies to chromogranin A and the mast cells were identified by toluidine blue staining. Histamine-immunoreactive endocrine cells were found almost exclusively in the acid-producing part of the stomach; only rarely were such cells observed in the pyloric gland area. They were fairly numerous in the gastric mucosa of the two subclasses of fish as well as in the amphibia and reptile species studied. Here, the majority of the histamine-immunoreactive endocrine cells seemed to have contact with the gastric lumen (open type cells) and were located in the surface epithelium (certain fish only) or together with mucous neck cells at the bottom of the pits. In the chicken, histamine-immunoreactive endocrine cells were numerous and located peripherally in the deep compound glands. They were without contact with the lumen (closed type) and had long basal extensions (paracrine appearance), running close to the base of the oxyntico-peptic cells. In mammals, the number of histamine-immunoreactive endocrine cells in the stomach varied greatly. They were particularly numerous in the rat and notably few in the dog, monkey and man. In all mammals, the histamine-immunoreactive endocrine cells were of the closed type and located basally in the oxyntic glands. They often had a paracrine appearance with long basal processes. Histamine-storing mast cells, finally, were few in both subclasses of fish as well as in the amphibian species and in the lizard. They were fairly numerous in chicken proventriculus (beneath the surface epithelium), few in the oxyntic mucosa of mouse, rat and hamster, moderate in number in hedge-hog, guinea-pig, rabbit, pig and monkey, and numerous in cat, dog and man. In the oxyntic mucosa of the latter three species mast cells sometimes seemed to have an intraepithelial localization which made their distinction from endocrine cells difficult. In newborn cats (1–3 days old) in human foetuses (17–24 weeks gestational age) mast cells were relatively few in the gastric mucosa and the histamine-containing endocrine cells were easier to demonstrate as a consequence. Patients with achlorhydria (and pernicious anemia) or suffering from hypergastrinemia due to gastrinoma had a greatly increased number of histamine-storing endocrine cells in the oxyntic mucosa compared with normal individuals.     

Proliferative reaction of the epithelium of gastric glands to vagotomy and sympathectomy

By means of autoradiography and metaphase arrest technique 24-hour rhythms and intensity of proliferative processes in the epithelium of gastric glands were studied, as well as morphometric status of these structures after vagotomy and drug sympathectomy in the rat. In both cases the reaction of glandular epithelium appeared with the increase of mitotic activity and the decrease of cell synchronization before the entry into DNA--synthesis and mitosis. The number of epithelial cells in gastric glands became reduced, but after vagotomy, unlike sympathectomy, mainly because of the lack of chief cells. Thus, the trophic control upon the dynamic structure of gastric glands may have different mechanisms of realization for parasympathetic and sympathetic nervous system, probably, through the influence on cell proliferation or differentiation.     

Apelin cells in the rat stomach

Apelin is a recently discovered peptide that is the endogenous ligand for the APJ receptor. Apelin is produced in the central nervous system, heart, lung, mammary gland and gastrointestinal (GI) tract. The aim of this study was to identify by immunohistochemistry (IHC) cell types in the rat stomach that produce apelin peptide. IHC revealed abundant apelin-positive cells, primarily in the neck and upper base regions of the gastric glands in the mucosal epithelium. Apelin is not detected in the muscle layer. Apelin-positive cells were identified as mucous neck, parietal cells, and chief cells. Apelin is also identified in gastric epithelial cells that produce chromogranin A (CGA), a marker of enteroendocrine cells. The findings that apelin is expressed in gastric exocrine and endocrine cells agrees with and extends other data showing that apelin peptide is measurable in the gut lumen and in the systemic circulation by immunoassay.     

Immunohistochemical detection of lactoferrin of human milk in the tissues of the human and the fetus

By means of the indirect immunoperoxidase method in deparaffinized slices a comparative investigation on distribution of the female milk lactoferrin (LF) in tissues of the mature person and in the fetus has been performed. LF is revealed in cells of the neutrophil line of the mature person and of the fetus and in the secretory epithelium of some organs of the mature person (in the mammary, submandibular and parotid salivary glands, in the bronchial mucous membrane glands in the fundal and pyloric glands of the stomach). In all the cases investigated LF is revealed in the cells producing serous secrete: in the cells of the serous terminal parts and in the serous semilunar mixed terminal parts of the salivary glands, in the serous cells of the bronchial glands and in the chief cells of the gastric mucous membrane glands. In the fetal secretory epithelium of the organs LF is not found. As LF is revealed in the secretory epithelium of the mature person and is not revealed in the corresponding epithelium of the fetus, it should be considered as a marker of the cells, that reach certain degree of differentiation.     

Transdifferentiation of mucous neck cells into chief cells in fundic gastric glands shown by GNA lectin histochemistry

The epithelium of the gastric mucosa and its glands in the corpus of rat stomach contains mucous surface cells (MSCs), parietal cells, mucous neck cells (MNCs), zymogenic or chief cells (ZCs), several types of enteroendocrine cells, and intermediate cells with characteristics between MNCs and ZCs also called transitional or prezymogenic cells (pre-ZCs).The aim of our work was to analyze the expression of Mannose (Man) in the rat gastric glands by means of Galanthus nivalis lectin (GNA) histochemistry to identify the differences between MNC, pre-ZCs and ZCs and to establish the relationships between these cells. Most of the cytoplasm of MNCs was negative for GNA histochemistry. Intensity of GNA labeling in the gastric gland showed a graduation from pre-ZCs (weak labeling) to ZCs (moderate labeling). Labeling of ZCs was stronger at the perinuclear and apical cytoplasm.In the last years, strong evidence has been reported supporting that ZCs differentiate from MNCs. Our work also supports the origin of ZCs from MNCs, because the GNA labeling graduation might be due to oligosaccharides which are not expressed in MNCs, start to express in pre-ZCs and are more abundant in ZCs, indicating that differentiation from MNCs to ZCs is a process in which glycans with Man moieties are synthesized.     

Expression of neuronal nitric oxide synthase in several cell types of the rat gastric epithelium.

The aim of this study was to identify which cell types of the rat gastric epithelium express neuronal nitric oxide synthase (nNOS) because the results of the previous studies have been very divergent regarding this point. By the combination of immunohistochemical (IHC) and in situ hybridization (ISH) techniques, we detected expression of nNOS in chief and mucosecretory cells of the gastric epithelium. Moreover, some gastric endocrine cells were immunoreactive for nNOS, although they could not be distinguished in sections treated with ISH techniques. The strongest signal for all antibodies in IHC techniques was obtained when microwave (MW) heating was performed before the IHC procedure. Our results indicate that in the gastric epithelium a variety of cell types are able to produce NO. The NO produced by the different cell types (chief, mucous, and endocrine) may form a complex network of paracrine communication with an important role in gastric physiology.     

Age and changes in the number of endocrine cells in the stomach and their role in senile atrophy of the gastric glands

In the gastric mucous membrane of 40 rats representing 4 age groups (pubertal, mature, old and very old age) per 10 animals in each, thickness of the mucous membrane has been measured by the argyrophil method of Grimelius and the argentaffin method of Masson - Hamperl and the number of the endocrine cells has been counted. The thickness of the mucous membrane and the length of its glands, as well as the number of argyrophil cells increase from the pubertal towards the mature age. From the mature up to the old age the number of argyrophil cells rises in the antral part, and in the acid-producing zone it significantly decreases. The number of argentaffin cells in the stomach does not change from the pubertal towards the old age. In the very old age, against the background of atrophy of gastric glands, the number of both argyrophil and argentaffin cells decreases in both parts of the stomach studied. The data obtained are discussed taking into consideration functional role of various types of endocrine cells, producing biologically active peptides and monoamines.     

The fine structure of the stomach mucosa of the llama (Llama guanacoe)

Summary The epithelium of the fundic region mucosa of the hind stomach in the Llama guanacoe has been studied using morphological and histochemical methods. Morphology suggests that solute and water absorption may occur in the epithelium of the surface and of the foveolae, although this absorption can not be estimated because of the extensive secretion of the gastric glands. The same cells of the surface and foveolar epithelium show numerous secretory granules. The glands reveal neck cells, chief cells, a large number of oxyntic cells, four types of endocrine cells (A-like, ECL, D and EC), brush cells and wandering cells. PAS and Alcian blue reactions for light microscopy suggest a secretion of neutral and acidic mucosubstances in the surface and foveolar epithelium, of neutral mucosubstances only in the neck cells. Periodic acid-thiocarbohydrazide silver proteinate (PA-TCH-SP) reaction for electron microscopy confirms the presence of neutral mucosubstances within the secretory granules of the surface, foveolar and neck epithelial cells. In all these cells, the reaction product is also evident within sacculi and vesicles of the maturing surface of the Golgi apparatus. A positive PA-TCH-SP reaction also occurs on the membrane (and not on the contents) of the Golgi apparatus (maturing surface) and of the secretory granules of the chief cells as well as on the membrane of the Golgi apparatus and of apical vesicles and tubules of the oxyntic cells. In addition, silver granules slightly enhance the electron density of the contents of the secretory granules in the endocrine cells. Morphological and histochemical findings are discussed and compared with results described by others for monogastric mammals.     

Immunohistochemical studies of the distribution of a basolateral-membrane protein in intestinal epithelial cells (GZ1-Ag) in rats using monoclonal antibodies

The monoclonal antibody (mAb), GZ1, is specific for a 42-kilodalton (kD) protein (designated GZ1-Ag) present among the plasma membrane (PM) proteins of the absorptive cells of rat intestine. This protein only occurs in the basolateral PM and is absent from the microvillus membrane. GZ2 and GZ20 are two other mAbs that are also directed against GZ1-Ag but which specify other antigenic determinants of this protein than mAb GZ1. Used together, these three mAbs allow better characterization of GZ1-Ag and more precise investigation of its distribution and localization in various rat cells. We performed immunohistochemical labelling for GZ1-Ag at both the light- and electron-microscope levels and found that GZ1-Ag is extensively distributed in rat epithelial tissues. However, the amount of this protein present in epithelial tissue shows considerable variation. GZ1-Ag is not present in the secretory cells of terminal portions of most excretory glands or in cells of the endocrine glands and liver. The cells of kidney tubules, except for collecting tubules, also lack GZ1-Ag. Only small amounts of GZ1-Ag are present in the cells of the stratified squamous epithelium and transitional epithelium, the exception being superficial cells. High concentrations of GZ1-Ag occur in the excretory duct systems of glands and in the various kinds of epithelium present in the male and female genital tract. Our results also indicated that the GZ1-Ag in all of these cells has a very similar structure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ontogeny of some endocrine cells of the digestive tract in sea bass (Dicentrarchus labrax): An immunocytochemical study

Serotonin- and ten peptide-immunoreactive (IR) cell types were identified in the digestive tract of sea bass (Dicentrarchus labrax L.) larvae of four morphofunctional phases ranging in age from hatching to 61 days. The sequence of appearance and location of endocrine cells during ontogenetic development of the larvae was determined. The differentiation of endocrine cells followed a distal-proximal gradient in the gut which paralleled the morphofunctional differentiation. Serotonin-IR cells were identified in the last portion of the digestive tract from phase I onwards and in the gastric region from phase III, before these regions were morphofunctionally differentiated; met-enkephalin-IR cells were identified from phase II onwards in both the differentiated rectum and the undifferentiated intestine; cholecystokinin (CCK)- and synthetic human gastrin-34-IR cells were located only in the intestine and first found in the undifferentiated intestine of phase II; human gastrin-17-, peptide YY (PYY)- and neuropeptide Y (NPY)-IR cells appeared in the intestine from phase II and in stomach in phase IV, when it showed gastric glands; pancreatic polypeptide (PP)- and glucagon-IR cells were observed in both intestine and stomach, but insulin- and somatostatin-IR cells only in stomach, from phase III, during which the intestine but not the stomach was differentiated. PP- and PYY-, PP- and glucagon-, and PYY- and glucagon-like immunoreactivities coexisted from their first appearance in some cells of the gut.     

Ultrastructural study of the endocrine cells of the abomasum mucosa in pre-ruminant calves

During a systematic ultrastructural study on the endocrine/paracrine cells of the gastro-intestinal tract of ruminants, the aim of present work is to describe these cells in the abomasum of suckling calf. Taking into account all the cytological details, and especially the morphological appearance and the cytochemical reactivity of secretory granules, several endocrine cell types can be distinguished. Some of them (EC, D, D1) are common to all three of the glandular regions, whereas others are typical of cardiac and proper gastric glands: they are ECL, X, A-like and a fourth type, whose classification is uncertain. The last type (G cells) is detectable in pyloric glands only. The cardiac and proper gastric glands of the suckling calf abomasum contain two additional cell types, not present in bulls, A-like cells and the fourth type, and contain D1 cells which form a heterogeneous family. These data show a morphofunctional similarity between the abomasum of the suckling calf and the stomach of non-ruminant mammals.     

Specific localization of hepatic fatty acid-binding protein in the gastric brush cells of rats

Summary An immunocytochemical study by light- and electron microscopy using the antibody against rat hepatic fatty acid-binding protein (FABP) revealed the brush cells in the gastric epithelium of rats to be intensely immunoreactive. The immunoreactive cells were present in a group in the distal wall of the groove between forestomach and glandular stomach, as well as scattered singly in the surface and foveolar epithelia of the glandular stomach. Almost all immunoreactive brush cells had a thin basal process in contact with the basement membrane. No secretory granules with dense cores, similar to those of endocrine cells, were observed in the brush cells. The specific appearance of FABP-immunoreactivity in the brush cell indicates that this cell type is a distinct entity from other epithelial cells in the stomach and that FABP is a useful histochemical marker of the brush cells. FABP may be involved in the specific function(s) of this cell type related to fatty acid metabolism.     

Endocrine cells of the esophageal glands]

Distribution of endocrine cells in the human oesophagus was studied histochemically. Large amount of endocrine cells was discovered in terminal parts and excretory ducts of the cardial glands. Endocrine cells of the oesophageal cardial glands are represented, at least, by three types: argentaffine, argyrophil in the reactions of Grimelius and Sevier, Munger and argyrophil in the reaction of Grimelius only. The amount of argentaffine cells in the oesophageal cardial glands was observed to be 5 times as large as that of in the gastric cardial glands. The reason is evidently in functional difference of the oesophageal and gastric cardial glands. The endocrine cells were absent in the mucous glands of the oesophagus.     

Immunohistochemical studies of the distribution of a basolateral-membrane protein in intestinal epithelial cells (GZ1-Ag) in rats using monoclonal antibodies

Summary The monoclonal antibody (mAb), GZ1, is specific for a 42-kilodalton (kD) protein (designated GZ1-Ag) present among the plasma membrane (PM) proteins of the absorptive cells of rat intestine. This protein only occurs in the basolateral PM and is absent from the microvillus membrane. GZ2 and GZ20 are two other mAbs that are also directed against GZ1-Ag but which specify other antigenic determinants of this protein than mAb GZ1. Used together, these three mAbs allow better characterization of GZ1-Ag and more precise investigation of its distribution and localization in various rat cells. We performed immunohistochemical labelling for GZ1-Ag at both the light-and electron-microscope levels and found that GZ1-Ag is extensively distributed in rat epithelial tissues. However, the amount of this protein present in epithelial tissue shows considerable variation. GZ1-Ag is not present in the secretory cells of terminal portions of most excretory glands or in cells of the endocrine glands and liver. The cells of kidney tubules, except for collecting tubules, also lack GZ1-Ag. Only small amounts of GZ1-Ag are present in the cells of the stratified squamous epithelium and transitional epithelium, the exception being superficial cells. High concentrations of GZ1-Ag occur in the excretory duct systems of glands and in the various kinds of epithelium present in the male and female genital tract. Our results also indicated that the GZ1-Ag in all of these cells has a very similar structure. In all cells, GZ1-Ag is localized in the PM, but it is present throughout the entire PM only in the cells of the stratified squamous epithelium and in the basal and intermediate cells of the transitional epithelium. In all epithelial cells bordering directly on the lumen, it is only present in the basolateral part of the PM, being absent from the luminal PM.