The distribution of endocrine cells along the mouse intestine: A quantitative immunocytochemical study

The topographical distribution of endocrine cells in the crypt and villus epithelium along the length of the mouse intestine was studied. Argyrophil reactivity using the Grimelius stain was used to estimate the total endocrine population of the intestine. Comparisons were then made with the fraction of endocrine cells containing glucagon like material, stained immunocytochemically using rabbit anti-glucagon antisera. A highly significant reduction in the incidence of endocrine cells (argyrophil reactive) from the proximal to distal end of the intestine was noted. However, only 10-30% of these cells contained glucagon like material in the crypts of the duodenum, jejunum and ileum, compared to 30–60% in the crypts of the colon and rectum. The distribution of endocrine cells (argyrophil reactive) was maximal in the lower regions of the proliferative zone of the crypts but showed no significant variation along the length of the villi. Cells containing glucagon like material were also most frequent in the lower regions of the proliferative zone of the crypts, but were not generally found above the botom third of the villi. Each crypt in the small intestine contains between 3 and 5 endocrine cells one of which contained glucagon like immunoreactive material. In the colon and rectum each crypt contains about 6-8 endocrine cells, of which 3–4 contained glucagon like immunoreactive material. These results indicate that a sub-set of cells containing glucagon like material, differentiate early in the lineage of endocrine cells within the proliferative zone of the intestinal crypts.     

The distribution of endocrine cells along the mouse small intestine

The topographical distribution and incidence of endocrine cells in the crypt and villus epithelium and along the length of the mouse intestine was studied. Cells containing somatostatin and bombesin like reactivity were stained by immunocytochemical techniques using polyclonal antiserum. Most of the somatostatin cells were found in the duodenum, jejunum and ileum, and these cells were generally more frequent on the villus compared to the crypts. This may indicate that the somatostatin cells develop late in the endocrine cell lineage. Bombesin like cells were rare in occurence, and were only present in measureable numbers in the ileum, where they were observed in the crypt and villi. The application of ELISA assays to determine the specificity of the antisera for these peptides is also discussed.     

The distribution of endocrine cells along the mouse small intestine. Bombesin and somatostatin producing cells

The topographical distribution and incidence of endocrine cells in the crypt and villus epithelium and along the length of the mouse intestine was studied. Cells containing somatostatin and bombesin like reactivity were stained by immunocytochemical techniques using polyclonal antiserum. Most of the somatostatin cells were found in the duodenum, jejunum and ileum, and these cells were generally more frequent on the villus compared to the crypts. This may indicate that the somatostatin cells develop late in the endocrine cell lineage. Bombesin like cells were rare in occurrence, and were only present in measureable numbers in the ileum, where they were observed in the crypt and villi. The application of ELISA assays to determine the specificity of the antisera for these peptides is also discussed.     

The endocrine pancreas of Triturus cristatus: an immunocytochemical study

The endocrine pancreas of Triturus cristatus carnifex was studied with the aid of immunocytochemical methods, showing cells immunoreactive to anti-insulin serum (B cells), a small population of cells immunoreactive to anti-glucagon serum only (A cells), rare cells positive to anti-PP serum only (PP or F cells), and a larger population of cells immunoreactive both to anti-glucagon and to anti-PP sera. B cells lied in the core of the islet, while the A/PP cells were located at the periphery, forming digitations extending into the exocrine parenchyma. D cells were present in small number in the islet while they were more numerous scattered in the exocrine parenchyma. A/PP cells as well as D cells showed one or two long cytoplasmic extensions often in contact with blood vessels.     

Ontogenesis of endocrine cells in the chicken intestine: an immunohistochemical study

The authors report the time of appearance, morphology and topographic distribution of gastrin/cholecystochinin- (G/CCK-), somatostatin- (SRIF-), neurotensin- (NT-), motilin- (MO-) and substance P-like immunoreactive (SP-LI) elements during embryonic and postnatal development, in ileum, caeca and colon of chick embryos (from 8 days of incubation to hatching), newborn chicks (up to 15-days old) and adult chickens. In the ileum, G/CCK-LI and SP-LI cells appeared on day 11, the others on about day 13. In the caeca the first cells of all types were seen from about day 17. In the colon, NT-LI cells appeared early, on day 9, SP-LI and occasional SRIF-LI cells from day 13 on and MO-LI and G/CCK-LI only from day 17. In the ileum all the cells studied were present, in the caeca and colon they were extremely scarce, apart from NT-LI cells which were more numerous. In the prenatal stages, SP-LI was found only in epithelial cells; after hatching, it was also present in metasympathetic nerve elements.     

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.     

Transendothelial transport of serum albumin: a quantitative immunocytochemical study

The steady-state distribution of endogenous albumin in mouse diaphragm was determined by quantitative postembedding protein A-gold immunocytochemistry using a specific anti-mouse albumin antibody. Labeling density was recorded over vascular lumen, endothelium, junctions, and subendothelial space. At equilibrium, the volume density of interstitial albumin was 18% of that in circulation. Despite this large difference in albumin concentration between capillary lumen and interstitium, plasmalemmal vesicles labeling was uniformly distributed across the endothelial profile. 68% of the junctions displayed labeling for albumin, which was however low and confined to the luminal and abluminal sides. The scarce labeling of the endothelial cell surface did not confirm the fiber matrix theory. The kinetics of albumin transcytosis was evaluated by injecting radioiodinated and DNP-tagged BSA. At 3, 10, 30, and 60 min, and 3, 5, and 24 h circulation time, blood radioactivity was measured and diaphragms were fixed and embedded. Anti-DNP antibodies were used to map the tracer in aforementioned compartments. A linear relationship between blood radioactivity and vascular labeling density was found, with a detection sensitivity approaching 1 gold particle per DNP-BSA molecule. Tracer presence over endothelial vesicles reached rapidly (10 min) a saturation value; initially localized near the luminal front, it evolved towards a uniform distribution across endothelium during the first hour. An hour was also needed to reach the saturation limit within the subendothelial space. Labeling of the junctions increased slowly, out of phase with the inferred transendothelial albumin fluxes. This suggests that they play little, if any, role in albumin transcytosis, which rather seems to proceed through the vesicular way.     

Ontogeny and distribution of certain endocrine cells in the human fetal large intestine

Summary In 9 fetuses, 9 to 24 weeks-old, the occurrence and relative distribution of argentaffin cells, as well as of cells immunoreactive to somatostatin (SRIF), glucagon-like polypeptide (GLI), pancreatic polypeptide (PP) and substance P (SP) were studied in five segments of the colon (appendix, cecum, ascending colon, descending colon, and rectosigmoid). For each colonic segment, data concerned with the occurrence of endocrine cells were expressed either as mean absolute numbers of specific cells per entire mucosal section, or as cell densities per mm³ of mucosa after calculation of the mucosal volume of the sections. Argentaffin, GLI, SRIF and PP immunoreactive cells are all present in relatively large numbers, scattered along the entire length of the colonic mucosa as early as the 9th–10th week of gestation, whereas substance P-containing cells occur sporadically and first appear during the 14th–17th week. Until the 20th week, with progressing embryonic development, an increase was determined in absolute numbers per section of all types of endocrine cells in all segments of the colon. This observation is clearly related to the general growth of the colonic mucosa, since cell densities per mm³ of mucosa do not greatly change or even decrease during gestation. However, it is possible that densities of argentaffin, GLI and BPP cells increase in the appendix around the 14th–17th week of gestation. Between the 20th and 24th week, absolute numbers of cells per section remain stable or slightly increase, while cell densities tend rather to decrease in all segments. These data demonstrate that some endocrine cells are present very early in the human fetal colon, but their functional significance remains to be elucidated.This work was supported by the Institut National de la Santé et de la Recherche Médicale (INSERM)     

An immunocytochemical study of endocrine pancreas of snakes

Summary The pancreas from eleven species of snakes representing both advanced and primitive families has been investigated for the presence of eleven regulatory peptides reported to occur in the mammalian endocrine pancreas. Of the eleven peptides studied, insulin, pancreatic glucagon and somatostatin were present in endocrine cells within the islets of all the species investigated. The neuropeptide, vasoactive intestinal polypeptide, was located within nerve terminals innervating the islets in the Boidinae, Colubrinae, Elaphidae and Crotalidae but absent from the Natricinae investigated.No immunoreactivity was demonstrable with the antisera to substance P, met-enkephalin, C-terminal gastrin, bombesin, glicentin and gastric inhibitory polypeptide. Pancreatic polypeptide-like immunoreactivity was demonstrable only in the boid snakes and exclusively stained by a C-terminal specific antiserum.     

An immunocytochemical study of the distribution of pancreatic endocrine cells in chicks,with special reference to the relationship between pancreatic polypeptide and somatostatin-immunoreactive cells

Summary Araldite sections of formalin-fixed pancreas from chicks at hatching were treated by an indirect immuno-enzyme technique to reveal cells containing APP, somatostatin, glucagon and insulin.APP cells were found scattered in the exocrine parenchyma. A few were associated with insulin-containing B islets and occasional cells occurred in and around glucagon-containing A islets. Somatostatin-immunoreactive cells were distributed peripherally in A and B islets and were dispersed in the exocrine tissue. APP cells were roughly as numerous in the exocrine parenchyma as somatostatin-immunoreactive cells.Since certain published observations point to the possible occurrence of APP and somatostatin in the same cells, consecutive sections were stained for these hormones. In no case did the two peptides occur in the same cell. Sections subjected to double-staining confirmed this result. Therefore it is likely that the described differences between APP and somatostatin-immunoreactive cells are valid.     

Calmodulin in mouse male germ cells: a qualitative and quantitative study

Isolated male germ cells of the mouse possess a heat-stable stimulatory activity of Ca2+-dependent, calmodulin-free phosphodiesterase. Ionic exchange chromatography allowed partial purification of the activator and the isolation of multiple forms of phosphodiesterase stimulation inhibitor. The activator has been identified as calmodulin on the basis of chromatographic behaviour and electrophoretic mobility. Quantitative analysis showed variations of calmodulin levels at different stages of spermatogenesis. Quantitative analysis of cyclic nucleotide hydrolysis in germ cell cytosol showed that the activity of Ca2+-dependent phosphodiesterase is different in meiotic and post-meiotic mouse male germ cells. These data suggest that calcium-dependent pathway and a Ca2+-dependent regulation of cyclic nucleotides are present in developing germ cells.     

An immunocytochemical study of the distribution of pancreatic endocrine cells in chicks, with special reference to the relationship between pancreatic polypeptide and somatostatin-immunoreactive cells.

Araldite sections of formalin-fixed pancreas from chicks at hatching were treated by an indirect immuno-enzyme technique to reveal cells containing APP, somatostatin, glucagon and insulin. APP cells were found scattered in the exocrine parenchyma. A few were associated with insulin-containing B islets and occasional cells occurred in and around glucagon-containing A islets. Somatostatin-immunoreactive cells were distributed peripherally in A and B islets and were dispersed in the exocrine tissue. APP cells were roughly as numerous in the exocrine parenchyma as somatostatin-immunoreactive cells. Since certain published observations point to the possible occurrence of APP and somatostatin in the same cells, consecutive sections were stained for these hormones. In no case did the two peptides occur in the same cell. Sections subjected to double-staining confirmed this result. Therefore it is likely that the described differences between APP and somatostatin-immunoreactive cells are valid.     

Distributions of the endocrine cells in the gastrointestinal tract of nectarivorous and sanguivorous bats: A comparative immunocytochemical study

The present study was conducted to clarify the influence of feeding habits on regional distribution and relative frequency of endocrine cells secreting cholecystokinin (CCK), gastrin (GAS), serotonin (5-HT) and enteroglucagon (GLUC) in the nectarivorous Anoura geoffroyi and Glossophaga soricina and the sanguivorous Desmodus rotundus bats of the Phyllostomidae family, by specific immunohistochemical methods. The regional distribution and frequency of the different types of endocrine cells varied according to their location in the GIT. 5-HT immunoreactive cells (IR), detected throughout the GIT of three bats, were the most predominant gastrointestinal endocrine cells. GAS-IR cells in A. geoffroyi were found at the base of the pyloric gland, while in G. soricina they could also be observed in the middle to basal portions of the gland. GLUC-IR cells were located in the fundic region of A. geoffroyi, G. soricina and D. rotundus. These endocrine cells were more abundant in the sanguivorous bat. In nectarivorous bats were compared to sanguivorous bat, which differ in dietary habits, difference in the distribution and relative frequency of gut endocrine cells would be predicted. The absence of some, and decrease in frequency of other, gastrointestinal endocrine cells may reflect, in part, its interspecies differences or dietary habits.     

An immunohistochemical study of the pancreatic endocrine cells of the ddN mouse

The regional distribution and frequency of the pancreatic endocrine cells in the ddN mouse were studied using specific antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (hPP). In the pancreatic islets, most of insulin-immunoreactive (IR) cells were located in the central region, and glucagon-, somatostatin and hPP-IR cells were located in the peripheral region regardless of the lobe. In the splenic part, glucagon-IR cells were also located in the central regions, and more numerous somatostatin-IR cells were detected in the central regions as compared with the duo-denal part. hPP-IR cells were restricted to the peripheral regions in both lobes but more numerous cells were detected in the duodenal portion. In the exocrine parenchyma of the splenic lobe, only insulin- and glucagon-IR cells were detected but all four kinds of IR cells were observed in the duodenal portion. In addition, insulin and hPP-IR cells were also demonstrated in the pancreatic duct regions. In conclusion, some strain-dependent characteristic distributional patterns of pancreatic endocrine cells were found in the ddN mouse with somewhat different distributional patterns between the two pancreatic lobes.     

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.     

The distribution of enterochromaffin cells in the human small intestine

Summary The distribution of argyrophile and argentaffin cells has been studied in the small intestine of five human adults. In proceeding cranio-caudally the characteristic feature of their distribution is the presence of eight to ten waves of rising and falling density. A progressive decrease in density of cells from duodenum to terminal ileum (described by previous workers) is not present.Re-examination of findings reported earlier in the small intestines of human foetuses shows that a predominant U shaped pattern of distribution is present in younger foetuses. This changes to the adult pattern by full term. The appearance of the adult pattern occurs earlier for argyrophile cells than for argentaffin cells.