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.     

Quantitative characteristics of the endocrine cells of the duodenal glands of Carnivora

In the duodenal glands of the Carnivora investigated endocrine elements have been revealed, a part of them is presented as serotonin-producing EC-cells. Endocrine cells are situated in terminal parts and in glandular ducts, among them elements of open and close types are distinguished. Distribution of these cells in the glandular lobules is subjected to the distal gradient regularity, specific for the gastrointestinal tract mucosal membrane. Amount of endocrinocytes in the glands is much less than in the gut crypts. There is no correlation between distribution of the endocrine cells in the glands and in the crypts. The results of unifactor analysis of variance demonstrate a slight effect of the taxonomic position of the species on the number of endocrine cells in the duodenal glands. The proper endocrine apparatus of the duodenal glands is supposed to produce a local regulatory influence on the secretory activity of exogenic glandulocytes, as well as ensure humoral connections of the duodenal glands with other parts of the gastrointestinal tract.     

An immunocytochemical and ultrastructural study of the larval anterior intestine of the frog Rana temporaria, with especial reference to endocrine cells

Endocrine cells of the larval intestine of Rana temporaria tadpoles have been identified by argyrophilic, immunocytochemical and electron-microscopical techniques. Scarce endocrine cells have been found in both the short non-absorptive zone immediately following the stomach, and in the rest of the anterior intestine. Endocrine cells are frequently seen to extend a cytoplasmic process towards the lumen. Immunoreactivity for serotonin, somatostatin, bombesin and cholecystokinin-8 has been detected. According to the ultrastructural traits of the endocrine granules, three larval intestinal endocrine populations have been differentiated.     

Neurotransmitters regulating acid secretion in the proventriculus of the Houbara bustard (Chlamydotis undulata): a morphological viewpoint

Endocrine cells containing somatostatin (Som), gastrin-releasing peptide (GRP), and neuronal nitric oxide synthase (nNOS) and nerve fibers containing choline acetyl transferase (ChAT), tyrosine hydroxylase (TH), galanin (Gal), substance P (SP), and vasoactive intestinal polypeptide (VIP) were immunolocalized in the proventriculus of the Houbara bustard, Chlamydotis undulata. While GRP-immunoreactive (GRP-IR) cells occur in the inner zone, somatostatin (Som-IR) and polyclonal nNOS (nNOS-IR) immunoreactive cells were localized mainly in the peripheral zone of submucosal glands. GRP-IR, Som-IR, and nNOS-IR cells were occasionally observed in the walls of the gastric glands. Endocrine cells are of the closed variety and usually possess apical processes extending along the basal surfaces of adjacent nonreactive cells. Ultrastructural features of these cells are typical. ChAT, Gal, SP, VIP, and TH were immunolocalized in nerve fibers and terminals in the walls of arterioles and capillaries at the periphery of submucosal glands. Immunoreactivity to monoclonal nNOS occurred mainly in neuronal cell bodies in ganglia located around the submucosal glands. ChAT and TH immunoreactive cell bodies were also occasionally seen around the submucosal glands in the peripheral region. Immunoreactivity to Gal, SP, and VIP, but not ChAT or TH, was discernible around the walls of gastric glands. It was concluded that the distribution of neurotransmitters in neuronal structures is similar, but that of the endocrine cells varies from that of some avian species. The roles of these neurotransmitters in the regulation of acid secretion are discussed.     

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.     

Quantitative electron microscopy of endocrine cells in oxyntic mucosa of normal human stomach

Summary An ultrastructural morphometric study of the endocrine cells of the oxyntic mucosa of the stomach in gastric biopsies collected from five male and five female healthy volunteers aged 19–31 was performed. No sex-related differences were disclosed. Endocrine cells accounted for 1.2±0.4% of the epithelial volume and 0.9±0.4% of the mucosal volume, i.e., including the lamina propria. After classification of the specific endocrine cell types according to the ultrastructural morphology of secretory granules, the volume densities of ECL, P and D cells (30±9%, 24±7%, and 22±4% of the entire endocrine cell mass, respectively) were higher than those of other endocrine cell types. In particular, EC cells contributed less than 10% and X cells represented a very low proportion of the total cells. Non-granulated profiles of cells which in all other respects appeared to be endocrine were also found with a volume density of 8±4%. D cells were distinguished by the high fraction of cytoplasm occupied by secretory granules (31±5%). Subdivision of the whole mucosa into four horizontal segments revealed the endocrine cells to be mostly distributed in the three lower, with virtually no endocrine cells in the superficial segment. The quantitative ultrastructural analysis of the endocrine cell population of the normal human oxyntic mucosa provided by this study may allow a better evaluation of physiological and pharmacological variations of the endocrine cell population.     

Endocrine cells in the prostate gland, urothelium and Brenner tumors. Immunohistological and ultrastructural studies

Endocrine cells are a normal constituent of the prostate gland, prostatic urethra and urinary bladder mucosa. Positive results using immunohistochemical technics were obtained only with antiserotonin antibodies. In normal tissues, there was a close similarity between the distribution of argyrophilic cells (Grimelius) and serotonin-storing cells. Some striking features were the patchy distribution of endocrine cells, the presence of slender cytoplasmic processes occasionally reaching the luminal surface and the paucity of specialized cells in bladder mucosa. It is unlikely that endocrine cells participate in conventional neoplasms of prostate and bladder. Exceptions are lobular hyperplasia, certain adeno-carcinomas of prostate and inverted papilloma of bladder. An ultrastructural study permitted the distinction of two types of endocrine cells characterized by a different morphology of their granules. Another relevant finding was the presence of serotonin-storing cells in Brenner tumors. The latter observation emphasizes the close similarity between this neoplastic epithelium and urothelium. This implies that endocrine cells may be of mesodermal derivation.     

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.     

Fine structure of the oxynticopeptic cells in the gastric glands of the ruin lizard, Podarcis sicula campestris De Betta, 1857

The results of an ultrastructural investigation of the gastric glands of the ruin lizard are reported. In this reptile the stomach can be divided into a larger fundus and a smaller pars pilorica. Fundic glands are characterized by three main kinds of cells: mucous, endocrine, and oxynticopeptic; the latter were not observed in the pyloric glands. The morphological features of the oxynticopeptic cells change from the proximal to the distal region of the fundic mucosa. In the proximal region, numerous electron-dense secretory granules, a well-developed granular endoplasmic reticulum, an evident Golgi complex, and a reduced system of smooth-surfaced vesicles and tubules in the apical cytoplasm characterize these cells. In the distal fundic region, oxynticopeptic cells possessed numerous mitochondria and a well-developed smooth-surfaced endoplasmic reticulum, but secretory granules were rare. These data suggest the existence of a gradient in the production of proteolytic enzymes, and perhaps also of hydrochloric acid, along the oral-aboral axis of the stomach. The results are discussed with regard to the evolution of the gastric glands and of the digestive mechanism in vertebrates.     

Electron microscopic identification of the histamine-storing argyrophil (enterochromaffin-like) cells in the rat stomach

Summary In the oxyntic gland area of the rat stomach the histamine-containing epithelial cells (also referred to as enterochromaffin-like cells because of their morphologic similarity with the 5-hydroxytryptamine-storing enterochromaffin cells) constitute the system of argyrophil cells in this area as previously shown by the combined use of fluorescence and light microscopic techniques. By performing the argyrophil staining reaction directly on ultra-thin sections it could be demonstrated in the electron microscope that the argyrophil cells have features suggesting that they are endocrine. Based on the ultrastructure of their secretory granules at least two such endocrine cell systems—both argyrophil—could be recognized in the oxyntic glands. The silver deposits were accumulated over the secretory granules of both these cell systems.It is well known that after injection of 1-3,4-dihydroxyphenylalanine, the histamine-storing (enterochromaffin-like) cells of the oxyntic glands store also dopamine. Under these conditions the enterochromaffin-like cells stain argentaffin, which has been shown at the light microscopic level. Also this reaction could be performed directly on ultra-thin sections. By electron microscopy it was then established that the two endocrine cell systems of the oxyntic gland area stained argentaffin upon treatment with 1-3,4-dihydroxyphenylalanine, and that the staining was confined to the secretory granules.The results clearly show that the enterochromaffin-like cells of the rat oxyntic gland area (which is devoid of 5-hydroxytryptamine-containing enterochromaffin cells) are identical with cells characterized as endocrine by ultrastructural criteria, and that gastric non-mast-cell histamine occurs in at least two separate systems of enterochromaffin-like cells.     

牛蛙胃肠胰系统内分泌细胞的免疫组织化学鉴定与定位

应用过氧化物酶标记的链霉卵白素(S-P)免疫组织化学方法对牛蛙(Rana catesbeiana)胃肠胰系统5种内分泌细胞进行了鉴定与定位.在消化道中检测到了5-羟色胺(5-HT)、生长抑素(SS)、胃泌素(Gas)和胰高血糖素(Glu)细胞.5-HT细胞主要分布于胃幽门部和空肠,食道中偶见.SS细胞主要分布于胃,幽门部较密集,小肠各段少量,直肠和食道偶见.Gas细胞主要分布于小肠各段,胃和直肠中偶见,食道中未检测到.Glu细胞主要分布于胃和直肠,小肠各段偶见,食道中未检测到.在胰腺中检测出了5-HT、SS、Gas、Glu和胰多肽(PP)细胞.SS、Glu和PP细胞数量较多,成簇分布于胰岛中,5-HT和Gas细胞少量,散在分布于胰腺腺泡之间.胃腺部和胰腺内分泌细胞多呈圆形、椭圆形或形态不规则,有的可见明显胞突伸向邻近细胞,胃肠道上皮中的内分泌细胞多呈梭形、楔形或锥形,有的可见明显胞突伸向消化腔.与其它两栖动物相比,牛蛙胃肠胰系统内分泌细胞的存在与分布有一些共性,也存在着种间差异.     

Immunocytochemical and ultrastructural characterization of endocrine cells in the larval stomach of the frog Rana temporaria tadpoles: a comparison with adult specimens

According to immunostaining and ultrastructural patterns, Rana temporaria tadpole stomach displays a well-differentiated endocrine population comprising, at least, six cellular types: ECL, EC [serotonin], D [somatostatin] - all three of them abundant -, P [bombesin] - less numerous -, CCK-8 [cholecystokinin/gastrin] and A [glucagon/glicentin] - both very scarce. Larval endocrine cells are mainly located in the surface epithelium and show open or closed morphologies. Cellular diversity is similar in tadpoles and frogs, with the exception of immunoreactivity for gastrin-17, found in adults in numerous cells. Larval cells display mature ultrastructural traits, although with smaller secretory granules. The different distribution of endocrine cells, which in adults are preferentially located in the glands, probably refers to different functional requirements. However, the rich vascular plexus present in larval mucosa may be an efficient transport medium of surface hormones to-gastric targets. The enhancement in adults of endocrine population and correlative increase in hormonal secretion indicates a more active functional role, probably related to the shift from herbivorous to carnivorous habits. In summary, the tadpole gastric endocrine population, although not as numerous as that of adult frogs, displays histological traits that indicate a relevant (immunoreactive and ultrastructural properties, cellular diversity) and specific (surface location, relative abundance of open-type cells) role of local regulatory factors in amphibian larval gastric function.     

Isolation and identification of EG-VEGF/prokineticins as cognate ligands for two orphan G-protein-coupled receptors

Endocrine gland-derived vascular endothelial growth factor (EG-VEGF, identical to prokineticin 1) is a novel peptide recently identified as a selective mitogen for endocrine gland endothelial cells. The present study demonstrates that EG-VEGF/prokineticin 1 and a peptide closely related to EG-VEGF, prokineticin 2, are cognate ligands of two orphan G-protein-coupled receptors designated ZAQ (=EG-VEGF/PK-R1) and I5E (=EG-VEGF/PK-R2). EG-VEGF/prokineticin 1 and prokineticin 2 induced a transient increase in intracellular calcium ion concentration ([Ca(2+)](i)) with nanomolar potency in Chinese hamster ovary (CHO) cells expressing EG-VEGF/PK-R1 and -R2 and bind to these cells with high affinity and with different receptor selectivity. EG-VEGF/prokineticins provoke rapid phosphorylation of p44/42 MAP kinase and DNA synthesis in the bovine adrenal capillary endothelial cells (BACE). The mRNAs of both EG-VEGF/PK-R1 and -R2 were expressed in BACE. The identification of the receptors for EG-VEGF/prokineticins may provide a novel molecular basis for the regulation of angiogenesis in endocrine glands.     

Cytodifferentiation of the epithelium of the gastric mucosa glands of rats in ontogenesis

Structure of epithelium in the mucous membrane glands of the rat stomach has been studied electron microscopically during embryonal and postnatal periods of development. Time of initial appearance of various types of cells in early stages of the gastric epithelium histogenesis has been verified. Asynchronity of their appearance is demonstrated. In epithelium of the gastric glands in 20-day-old rat embryos poorly differentiated exocrine and also endocrine D- and G-cells are revealed. On the 1st day EC-, ECl-, and on the 3d day--X-endocrinocytes appear. Neighbouring exocrinocytes connect with each other by means of both nonspecific and specific intercellular contacts. Exocrine and endocrine cells connect by means of desmosomes. For the animals of each age group certain range of ultrastructural organization in variously differentiated glandulocytes (they are morphological basis of the reactive changes) is specific.     

Ultrastructure of endocrine cells in the gastric fundal glands at different seasons of the year]

Endocrine cells of gastric glands of Citellus erythrogenus Brandt were studied during various seasons of the year by electron microscopy. ECL, EC, D and D1 cells having different structure of granules were detected. The slightly changed, weakly functioning cells as well as the cells of different alteration degree (up to destructing) were found in hibernating rodents. The presence of actively functioning EC-cells over this period confirms an opinion concerning the influence of peripheral serotonin on the hibernation mechanism. On the 3d--4th day of awakening pronounced activation of endocrine cells, their rejuvenation and normalization of cell ultrastructure, completed two weeks after awakening, were noted.     

Fine Structure of the Pars Distalis of the Pituitary Gland in the Female Mink,Mustela vison

Pituitary glands of intact and experimental adult females of mink, Mustela vison, were examined by electron microscopy. Conventional methods involving removal of endocrine glands (ovaries and adrenals), administration of radioactive isotope, ¹³¹I, blocking agents (thiouracil and metopirone) and hormones (thyroxine, hydrocortisone, thyrotropin and luteinizing hormone releasing hormones) were employed. Five categories of granular cells were distinguished both by their ultrastructural characteristics and qualitative changes throughout the year and following different treatments. The cell types are described and their functions discussed. From conventional electron microscopical studies it proved difficult to draw any satisfactory conclusions about the gonadotropic cells. Further investigation by means of immunocytochemistry and radioimmunoassay techniques is required to determine, whether the presumptive gonadotropic cell type produces both FSH and ICSH or only one of these hormones. Morphologically two types of agranular cells were identified. Their morphological inter-relationship and function are discussed briefly.     

三种鲤科鱼类肠道内分泌细胞的初探

使用Grimelius嗜银染色法对草鱼,鲤,翘嘴红鳇3种不同食性的鲤科鱼的肠道内分泌细胞进行了研究,在3种鱼的整个肠道上均发现有内分泌细胞的分布。在前肠前段中,内分泌细胞分布最多,愈向后分布愈少,在肠褶各处均有内分泌细胞分布,以基部分布最密,内分泌细胞几乎都为开放型,位于上皮细胞和杯状细胞之间,将胞突伸向肠腔,有极少数内分泌细胞兼有开放型和封闭型细胞的特点,在它们顶端胞突伸向腔的同时,基部也伸出突起将分泌物送入邻近细胞或细胞间隙中,肠上皮中还发现一种与内分泌细胞具有同样嗜银特性的圆形颗粒。     

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.     

On the occurrence of argyrophil cells in salivary glands

Summary Salivary glands (parotid, submandibular and sublingual glands) of nine mammalian species were investigated with respect to presence and localization of argyrophil and argentaffin cells. With the exception of the parotid gland of the rat, no positive staining was observed within the examined glands. In the rat parotid distinctly argyrophil cells could be demonstrated in the intercalated ducts. Histochemical studies of the cells, ultrastructural analysis of their cytoplasmic granules as well as their reactions to certain drugs indicate that these cells are of exocrine rather than of endocrine nature. After a subcutaneous injection of pilocarpine, the intensity of the argyrophil staining was markedly reduced. No specific catecholamine fluorescence could be detected within the cells, not even after pretreatment of the animals with high doses of L-DOPA. The membrane-bounded cytoplasmic granules of the intercalated duct cells furthermore displayed a strong positive staining reaction after treatment of ultrathin Vestopal sections with the periodic acid-chromic acid-silver technique of Rambourg et al. (1969).Supported by grants from the Swedish Medical Research Council (Project No. 12X-718), and the Medical Faculty of the University of Umeå. The skilful technical assistance of Miss Siw Domeij is gratefully acknowledged     

Morphological and functional changes in several endocrine glands induced by hypothyroidism in the rat

The effect of hypothyroidism upon the morphology and the function of several endocrine glands was studied in radiothyroidectomized male rats. It was found that T3, T4, insulin, prolactin and corticosterone levels were significantly lower in hypothyroid rats. TSH levels were significantly higher in these animals while no changes were depicted in testosterone levels. The administration of T4 drew back to normal range the above-mentioned altered serum hormone levels. The studies performed with light microscopy revealed alterations only in the TSH secretory cells of the adenohypophysis. Conversely, when using the electron microscope to study the different endocrine glands, clear alterations were depicted in the TSH and prolactin secretory cells of the adenohypophysis, as well as in the pancreatic B cells and the cells of the zona fasciculata of the adrenal cortex. No abnormal changes were demonstrable at the level of the seminiferous tubules of the testis. All the above morphological changes were corrected by the administration of T4 to hypothyroid rats. These results suggest that the hypothyroid state is a complex hormonal dysfunction rather than a single hormonal defect. The secretory alterations are accompanied by fine cellular alterations in the corresponding glands.