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.     

An immunohistochemical study of the insulin-, glucagon- and somatostatin-immunoreactive cells in the developing pancreas of the chicken embryo

The distributions and relative frequencies of insulin-, glucagon- and somatostatin-immunoreactive cells were studied in dorsal, ventral, third and splenic lobes of developing chicken pancreas during embryonic periods (10 days of incubation to hatching) by immunohistochemical methods. The regions of pancreas were subdivided into three regions: exocrine, light and dark islet. Round, oval and spherical shaped immunoreactive cells were detected in all four lobes. According to developmental stages, the types of lobes and the regions of pancreas showed various distributions and relative frequencies. In the splenic lobes, insulin, glucagon and somatostatin-immunoreactive cells were detected in exocrine, dark islet and light islet from time differentiation of splenic lobes, 13 days of incubation. The insulin- and somatostatin-immunoreactive cells of the third lobes were detected in exocrine and light islets from 10 days of incubation, and in dark islets from 15 and 11 days of incubation respectively. Glucagon-immunoreactive cells were detected in exocrine, dark and light islets from 16, 11 and 19 days of incubation respectively. These immunoreactive cells of the ventral lobes were detected in exocrine and light islets. However, dark islets were not found in this lobe. Insulin-immunoreactive cells were demonstrated from 10 days of incubation in these two regions. Glucagon-immunoreactive cells were detected from 17 days of incubation in exocrine and 16 days of incubation in the light islets. Somatostatin-immunoreactive cells were demonstrated from 11 days of incubation in exocrine and 14 days of incubation in the light islets. In the dorsal lobes, insulin-immunoreactive cells were demonstrated in exocrine, dark and light islets from 12, 14, and 13 days of incubation, respectively. Glucagon- and somatostatin-immunoreactive cells were detected in dark and light islets from 13 and 14 days of incubation, respectively. Glucagon- and somatostatin-immunoreactive cells were demonstrated from 10 and 11 days of incubation in exocrine respectively. Generally, insulin-immunoreactive cells were increased in light islets but decreased in light islets with developmental stages. However, glucagon-immunoreactive cells were decreased in light islets but increased in dark islets. In addition, somatostatin-immunoreactive cells showed the same frequencies in light and dark islets with developmental stages except exocrine which increased with developmental stages.     

Insulin-, glucagonand somatostatin-like immunoreactivity in the endocrine pancreas of the lungfish,Neoceratodus forsteri

Summary The endocrine pancreas of the Australian lungfish,Neoceratodus forsteri, was investigated immunocytochemically for the presence of polypeptide hormone-producing cells. Three cell types were identified, namely insulin-, glucagon-, and somatostatin-immunoreactive elements. The insulin cells are confined solely to the center of the islets. Glucagon and somatostatin cells are distributed peripherally around the central mass of the insulin cells. Isolated cells or clusters of glucagon and somatostatin cells are also dispersed within the exocrine parenchyma. The immunoreactive cell types are compared with those staining with standard histological procedures. The spatial relationships of the different cell populations are examined.     

An immunohistochemical study of the pancreatic endocrine cells of the nude mouse, Balb/c-nu/nu

The regional distribution and frequency of the pancreatic endocrine cells in the nude mouse, Balb/c-nu/nu were studied by immunohistochemical (peroxidase anti-peroxidase; PAP) methods using specific antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (hPP). The pancreas of the mouse was divided into two lobes, the splenic and duodenal lobes, and each lobe was subdivided into three regions, the pancreatic islets (central and peripheral regions), the exocrine region and the pancreatic duct region (consisting of duct epithelium and surrounding connective tissue--sub-epithelial connective tissue). 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 compared to those of the duodenal part. hPP-IR cells were restricted to the peripheral regions in both lobes but more numerous cells were detected in the duodenal portion as compared to those of the splenic portion. In the exocrine parenchyma of the splenic lobe, only insulin-, glucagon- and somatostatin-IR cells were detected.. Here, the insulin- and glucagon-IR cells formed cell clusters, while somatostatin-IR cells were present as solitary cells. In the exocrine region of the duodenal portion, only insulin-, somatostatin- and hPP-IR cells were observed, with the same distributional pattern as that found in the splenic lobe. However, clusters of cells consisting only of hPP-IR cells were distributed in the pancreas parenchyma as small islets. In the pancreatic duct region, only solitary hPP-IR cells were demonstrated in the sub-epithelial connective tissue regions of the splenic portion. In conclusion, some strain-dependent characteristic distributional patterns of pancreatic endocrine cells, especially of the hPP-IR cells, were found in the nude mouse. In addition, somewhat different distributional patterns were found between the two pancreatic lobes.     

The ultrastructural identity of pancreatic polypeptide cells in chicks

A very similar ultrastructure has been attributed to pancreatic polypeptide and somatostatin cells in chickens. In order to characterize any possible differences between them, cells shown to be immunoreactive for these hormones in semi-thin sections of chick pancreas were identified in adjacent thin sections prepared for conventional electron microscopy. In this way the ultrastructural features of the immunoreactive cells could be determined. In general, in somatostatin-immunoreactive cells, granule profiles are almost exclusively round, whereas in pancreatic polypeptide cells there are elongate as well round profiles. Within cells of both types the electron density of the granule matrix varies from one granule to another, but the range of density is greater in pancreatic polypeptide granules. The latter are slightly smaller than somatostatin granules.     

The ultrastructural identity of pancreatic polypeptide cells in chicks

Summary A very similar ultrastructure has been attributed to pancreatic polypeptide and somatostatin cells in chickens. In order to characterize any possible differences between them, cells shown to be immunoreactive for these hormones in semi-thin sections of chick pancreas were identified in adjacent thin sections prepared for conventional electron microscopy. In this way the ultrastructural features of the immunoreactive cells could be determined. In general, in somatostatin-immunoreactive cells, granule profiles are almost exclusively round, whereas in pancreatic polypeptide cells there are elongate as well as round profiles. Within cells of both types the electron density of the granule matrix varies from one granule to another, but the range of density is greater in pancreatic polypeptide granules. The latter are slightly smaller than somatostatin granules.     

Ontogeny of rat pancreatic polypeptide (PP) cells

Summary Cells storing pancreatic polypeptide (PP) appear in rat pancreas at the time of parturition, much later than insulin and glucagon cells. At this stage, the pancreatic polypeptide (PP) cells occur scattered in the exocrine parenchyma and in the islets. Subsequently, 5–7 days postnatally, an abrupt increase in the number of PP cells occurs. At this stage, they are fairly numerous in the islets and comparatively rare in the exocrine parenchyma. Not until 8–10 days after birth is the number of PP cells similar to that in the adult pancreas. A few PP cells were seen in the antral mucosa during the first 10 days after birth. They were not seen elsewhere in the gut.     

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.     

Catecholamine-containing pancreatic islet cells of the domestic fowl

Summary In an attempt to identify pancreatic islet cells emitting formaldehyde-induced fluorescence (FIF), the pancreatic islets of the domestic fowl were studied by combined fluorescence, ultrastructural, silver-impregnation and immunohistochemical methods in the same section or in consecutive semi-thin and ultra-thin sections. The results indicate that islet cells emitting intense FIF exhibit a strongly argyrophil reaction with the Grimelius' silver method and also immunohistochemical reaction with anti-glucagon serum, but not with anti-5-HT serum. Therefore, the fowl islet A cell, a peptide hormone-producing cell, stores simultaneously catecholamine as biogenic amine. The islet B and D cells did not display any FIF, any argyrophil reaction with the Grimelius' silver method, or any immunoreactivity with anti-glucagon or anti-5-HT sera. The fluorescent but non-argyrophil cells dispersed in the exocrine acinus may well be PP cells.     

Effects of CP 55,940--agonist of CB1 cannabinoid receptors on ghrelin and somatostatin producing cells in the rat pancreas

Cannabinoids participate in the modulation of numerous functions in the human organism, increasing the sense of hunger, affecting carbohydrate and lipid metabolism, and controlling systemic energy balance mechanisms. Moreover, they influence the endocrine system functions, acting via two types of receptors, CB1 and CB2. The aim of the present study was to examine the number, distribution and activity of ghrelin and somatostatin producing endocrine cells in the pancreas of rats after a single administration of selective CP 55,940 agonist of CB1 receptor. The study was performed on 20 rats. Neuroendocrine cells were identified by immunohistochemical reactions, involving specific antibodies against ghrelin and somatostatin. The distribution and number of ghrelin- and somatostatin-immunoreactive cells were separately studied in five pancreas islets of each section. A performed analysis showed a decreased number of somatostatin-immunoreactive cells and a weak immunoreactivity of ghrelin and somatostatin containing neuroendocrine cells in the pancreatic islets of experimental rats, compared to control animals. The obtained results suggest that a single administration of a selective CP 55,940 agonist of CB1 receptor influences the immunoreactivity of endocrine cells with ghrelin and somatostatin expression in the pancreas islets.     

Distribution and frequency of endocrine cells in the pancreas of the ddY mouse: an immunohistochemical study

The regional distribution and frequency of pancreatic endocrine cells in ddY mice were studied by an immunohistochemical (peroxidase anti-peroxidase; PAP) method using four types of 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 portion. Most of glucagon- and somatostatin-IR cells were observed in peripheral regions although a somewhat smaller number of cells were also located in the central regions. HPP-IR cells were randomly distributed throughout the entire islets. In the exocrine pancreas, insulin-, glucagon-, somatostatin- and hPP-IR cells were detected; they occurred mainly among the exocrine parenchyma as solitary cells. Cell clusters consisted of only insulin- or only glucagon-IR cells and were distributed in the pancreas parenchyma as small islets. In addition, insulin- and glucagon-IR cells were also demonstrated in the pancreatic duct regions. Insulin-IR cells were located in the epithelium and sub-epithelial connective tissue regions as solitary cells and/or clusters (3-4 cells), and glucagon-IR cells were mainly located in the epithelium as solitary cells. Overall, there were 63.89+/-5.39% insulin-, 26.52+/-3.55% glucagon-, 7.25+/-2.83% somatostatin- and 1.90+/-0.58% hPP-IR cells. In conclusion, some strain-dependent characteristic distributional patterns of pancreatic endocrine cells were found in the ddY mouse.     

胰岛淀粉样多肽在豚鼠胰腺分布的免疫组织化学研究

本文用免疫组织化学ＡＢＣ法,研究了胰岛淀粉样多肽（Ｉｓｌｅｔａｍｙｌｏｉｄｐｏｌｙｐｅｐｔｉｄｅ,ＩＡＰＰ或称Ａｍｙｌｉｎ）在豚鼠胰脏的分布,并用邻片免疫组织化学双标记法,观察了ＩＡＰＰ与胰岛素（Ｉｎｓｕｌｉｎ,ＩＮＳ）、生长抑素（ＳｏｍａｔｏｓｔａｔｉｎＳＳ）的共存关系。结果显示,豚鼠胰岛内绝大多数细胞都呈ＩＡＰＰ阳性免疫反应,在胰外分泌部的腺泡和导管内也散在分布有ＩＡＰＰ免疫反应阳性细胞。多数ＩＡＰＰ免疫反应阳性的细胞都显示ＩＮＳ免疫反应阳性,胰岛内少数ＩＡＰＰ阳性细胞也呈ＳＳ免疫反应阳性。说明ＩＡＰＰ主要分布在豚鼠的胰岛内．但也少量存在于外分泌部。ＩＡＰＰ主要和ＩＮＳ共存于Ｂ细胞内。但也和ＳＳ共存于Ｄ细胞内,提示ＩＡＰＰ可能通过自分泌途径调节ＩＮＳ和ＳＳ的分泌。     

An immunohistochemical study of pancreatic endocrine cells in SKH-1 hairless mice

The regional distribution and frequency of the pancreatic endocrine cells in the SKH-1 hairless mouse were studied by an immunohistochemical (peroxidase anti-peroxidase; PAP) method using four types of specific antisera against insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). The pancreas of mice were divided into three portions; pancreatic islets, exocrine and pancreatic ducts. The pancreatic islets were further subdivided into three regions (central, mantle and peripheral region) according to their located types of immunoreactive cells. In the pancreatic islet portions, insulin-immunoreactive cells were located in the central and mantle regions with 84.60 +/- 7.65 and 33.00 +/- 12.45/100 cells frequencies, respectively, but most of somatostatin-, glucagon- and PP-immunoreactive cells were detected in the mantle and peripheral regions. In the mantle region, somatostatin-, glucagon- and PP-immunoreactive cells were demonstrated with 28.70 +/- 9.91, 52.00 +/- 14.05 and 2.60 +/- 1.51/100 cells frequencies, respectively, and showed 6.20 +/- 2.86, 15.30 +/- 5.31 and 21.50 +/- 10.28/100 cells frequencies, respectively in peripheral regions. However, glucagon-immunoreactive cells were also demonstrated in the central regions with 4.00 +/- 2.83/100 cells frequency. In the exocrine portions, insulin-, glucagon-, somatostatin- and PP-immunoreactive cells were demonstrated in the SKH-1 mouse with 0.90 +/- 0.74, 0.80 +/- 0.79,4.90 +/- 3.54 and 2.70 +/- 1.34/100 cells frequencies, respectively. In the pancreatic duct portions, insulin-, glucagon- and somatostatin-immunoreactive cells were demonstrated in the subepithelial connective tissues and showed islet-like appearances with 30.30 +/- 14.67, 2.70 +/- 3.13 and 5.90 +/- 4.23/100 cells frequencies, respectively. However, no PP-immunoreactive cells were demonstrated in these regions. In conclusion, some peculiar distributional patterns of pancreatic endocrine cells were found in the SKH-1 hairless mouse.     

Pancreatic APUD cells in older chick embryos,with special reference to their identity

Summary Pancreatic APUD cells showing formaldehyde-induced fluorescence in Black Australorp chick embryos of nine to eighteen days of incubation, proved, on subsequent staining and silver impregnation, to be A, B, D and, from sixteen days, enterochromaffin (EC) cells. EC and D cells were scattered in the exocrine parenchyma, the latter cells increasing with time. Some groups of B cells were associated with large A islets from the ninth day of incubation onwards. The composition of A islets (A and some D cells) and B islets (B and some D cells) and the distribution attained (A islets in the splenic and third lobes; B islets in all lobes), accords with the situation reported for adults.     

Experimental study on the origin of pancreatic endocrine cells in the toad Bufo bufo L.

Summary Ablation, transplantation and culture experiments were used to determine the respective roles of the pancreatic dorsal and ventral anlagen in the formation of the endocrine cells. Three successive waves of endocrine formation occur in the pancreas of Bufo bufo at three developmental stages (III₆, IV₁ and IV₂). Each wave is derived from a different source: the first originates from the dorsal anlage, the second from the exocrine tissue of the cortex of the pancreas and the third from the pancreatic duct. Each generation of islets has a specific composition of different cell types. The first wave is only composed of insulin islets; the second wave gives rise to single insulin, glucagon and somatostatin cells; while the third wave generates single cells synthesizing one of the three hormones, homogeneous islets of insulin cells, rare glucagon islets and heterogeneous islets containing insulin cells in the centre and a few glucagon or somatostatin cells at the periphery.     

A light-microscopic immunocytochemical study of the endocrine pancreas in the Australian brush-tailed possum (Trichosurus vulpecula).

The endocrine pancreas of the Australian brush-tailed possum (Trichosurus vulpecula) was investigated by means of immunocytochemistry using the avidin-biotin-peroxidase technique. This was a light microscopic study using this established technique. Serial paraffin sections were stained individually with primary antibodies for glucagon, insulin, somatostatin, and pancreatic polypeptide (PP), showing the same islet. Cells immunoreactive to glucagon, insulin, somatostatin and PP were found in endocrine islets. PP cells appear to be scattered amidst the exocrine portion also. Insulin immunoreactive cells were located in the central region of islet, glucagon in the periphery, somatostatin in periphery and had elongated processes. PP cells were more sparse and located both in the periphery of islet and amidst the exocrine tissue. These results can then be related to a similar study in the same marsupial, but using the immunofluorescence technique and to studies in other marsupials such as grey kangaroo (Macropus fuliginosus) fat-tailed dunnart (Sminthopsis crasicaudata) and the American opossum (Didelphis virginiana). These investigations are part of a study in Australian mammals.     

Dissociation of Langerhans islets in the rabbit after pancreatic duct ligation. Immunocytochemical and ultrastructural studies

In the rabbit, pancreatic duct ligation leads to serious disturbances of the pancreatic endocrine parenchyma. Immunocytochemical studies conducted over a short period (between 5 and 30 days post ligation) allow observation of a progressive dissociation of the Langerhans islets which initially affects the splenic part of the pancreas, a region where numerous large islets are found. This dissociation is followed by a dispersion of small heterologous endocrine cell clusters or isolated endocrine cells in a connective tissue which replace the exocrine parenchyma. On the 30th day after ligation ultrastructural studies show marked degranulation of the B cells demonstrating the great fragility of these cells. These observations of insular dissociation, scattering of the different endocrine cells and impairment of B cells are often reported in experimental and pathological studies of the pancreas.     

Immunocytochemical study of the distribuition of endocrine cells in the pancreas of the Brazilian sparrow species Zonotrichia Capensis Subtorquata (Swaison, 1837).

In the present study, we investigated types of pancreatic endocrine cells and its respective peptides in the Brazilian sparrow species using immunocytochemistry. The use of polyclonal specific antisera for somatostatin, glucagon, avian pancreatic polypeptide (APP), YY polypeptide (PYY) and insulin, revealed a diversified distribution in the pancreas. All these types of immunoreactive cells were observed in the pancreas with different amounts. Insulin-Immunoreactive cells to (B cells) were most numerous, preferably occupying the central place in the pancreatic islets. Somatostatin, PPA, PYY and glucagon immunoreactive cells occurred in a lower frequency in the periphery of pancreatic islets.     

An immunocytochemical study of fetal cells at the maternal-placental interface using monoclonal antibodies to keratins,vimentin and desmin

Summary Thioredoxin and thioredoxin reductase (NADPH-oxidized thioredoxin oxidoreductase, E.C. 1.6.4.5) have been proposed to be involved in several thioldependent reduction-oxidation reactions in cells. Both proteins have been immunohistochemically demonstrated in the periphery of the cytoplasm and in cytoplasmic granules of acinar and islet cells in mouse pancreas. In animals fed ad libitum, the staining for thioredoxin was more intense in the exocrine acinar cells than in the islet cells, whereas that for thioredoxin reductase was more intense in the endocrine than in the exocrine pancreas. In the islets of fed mice all endocrine cell types showed about the same staining intensity for thioredoxin, while thioredoxin reductase was greatly enriched in the somatostatin-containing D cells. Starvation overnight caused an increased staining for both proteins in the acinar cells as well as in the islets. Under conditions of starvation, thioredoxin reductase, in contrast to thioredoxin, appeared to increase preferentially in the islet B cells, as compared with the D cells. Cysteamine treatment reduced the staining for somatostatin and for thioredoxin reductase in the D cells without any obvious effect on the other pancreatic cells. The results are compatible with a role for thioredoxin and thioredoxin reductase in secretion.     

The endocrine cells in the gastroenteropancreatic system of the bowfin, Amia calva L.: an immunohistochemical, ultrastructural, and immunocytochemical analysis.

The gastroenteropancreatic (GEP) endocrine system of bowfin (Amia calva) was described using light and electron microscopy and immunological methods. The islet organ (endocrine pancreas) consists of diffusely scattered, mostly small islets and isolated patches of cells among and within the exocrine acini. The islets are composed of abundant, centrally located B cells immunoreactive to bovine and lamprey insulin antisera and D cells showing a widespread distribution and specificity to somatostatin antibodies. A and F cells are present at the very periphery of the islets and are immunoreactive with antisera against glucagon (and glucagon-like peptide) and several peptides of the pancreatic polypeptide (PP)-family, respectively. The peptides of the two families usually collocates within the same peripheral islet cells and are the most common immunoreactive peptides present in the extra-islet tissue. Immunocytochemistry and fine structural observations characterised the granule morphology for B and D cells and identified two cell types with granules immunoreactive to glucagon antisera. These two putative A cells had similar granules, which were distinct from either B or D cells, but one of the cells had rod-shaped cytoplasmic inclusions within cisternae of what appeared to be rough endoplasmic reticulum. The inclusions were not immunoreactive to either insulin or glucagon antisera. Only small numbers of cells in the stomach and intestine immunoreacted to antisera against somatostatin, glucagon, and PP-family peptides. The paucity of these cells was reflected in the low concentrations of these peptides in intestinal extracts. The GEP system of bowfin is not unlike that of other actinopterygian fishes, but there are some marked differences that may reflect the antiquity of this system and/or may be a consequence of the ontogeny of this system in this species.