Immunocytochemical investigation of the gastro-enteropancreatic (GEP) neurohormonal peptides in the pancreas and gastrointestinal tract of the dogfishSqualus acanthias

Summary The pancreas and gastrointestinal tract (GIT) of adults and of an embryonic stage of 11 cm long (about half the length of newborn fish) of the spiny dogfish,Squalus acanthias, were investigated immunocytochemically for the occurrence of the gastro-entero-pancreatic (GEP) neurohormonal peptides. In the pancreas of adult forms 5 endocrine cell types were seen, namely insulin-, somatostatin-, glucagon-, pancreatic polypeptide (PP)- and gastric inhibitory peptide (GIP)-immunoreactive cells. These cell types form scatterd islets and were seen sometimes to surround small ducts. GIP-immunoreactivity cells did not occur in glucagon-containing cells. In the mucosa of GIT of adults 18 endocrine cell types were observed, viz. insulin-, somatostatin-, glucagon-, glicentin-, PP-, polypeptide YY (PYY)-, vasoactive intestinal polypeptide (VIP)-, GIP-, gastrin C-terminus, CCK-, neurotensin N-terminus-, bombesin/gastrin releasing peptide (GRP)-, substance P-, enkephalin-, -endorphin, -endorphin-, serotonin- and calcitonin immunoreactive cells. These cells occurred mostly in the intestine. All these cell types were of the open type, except glucagon- and glicentin-immunoreactive cells in the stomach, which seemed to be of the closed type. In the muscle layers and the submucosa, VIP and substance P-immunoreactive nerves and neurons were observed. In the pancreas of the dogfish embryo only 3 endocrine cell types could be demonstrated, namely insulin-, somatostatin- and glucagon-immunoreactive cells. In the mucosa of the GIT of the embryos studied 12 endocrine cell types were detected, viz. insulin-, somatostatin-, glucagon-, PP-, PYY-, VIP, GIP, gastrin C-terminus-, CCK-, neurotensin N-terminus-, enkephalin- and serotonin immunoreactive cells. The number of these cells, except that of PYY-immunoreactive cells, was lower than that of adults and in some cases their distribution did not correspond with that of adults.     

Immunocytochemical identification and localization of peptide hormones in the gastro-entero-pancreatic (GEP) endocrine system of the mouse and a stomachless fish, Barbus conchonius

A large number of antisera mainly raised against mammalian hormones are tested immunocytochemically on the GEP-endocrine system of mouse and fish (Barbus conchonius). The endocrine pancreas of mouse and fish appeared to contain the same four endocrine cell types; insulin-, glucagon-, PP- and somatostatin-immunoreactive cells. In mouse about 13 GEP endocrine cell types are distinguished: 1. insulin-, 2. somatostatin-, 3. glucagon-, 4. PP-, 5. (entero)glucagon-/PP-like, 6. CCK-like, 7. substance P-, 8. neurotensin-, 9. VIP-, 10. gastrin-, 11. secretin-, 12. beta-endorphin-, 13. serotonin-immunoreactive cells. Based on this and a previous study at least 13 GEP endocrine cell types seems to be present in stomachless fish: 1-9 as described for mouse, 10. (entero)glucagon-like, 11. met-enkephalin, 12. VIP-like, 13. unspecific immunoreactive endocrine cells. Coexistence of glucagon and PP-like peptides is found in the gut and pancreas of mice and in the gut of B. conchonius. In mouse pancreas and fish gut, endocrine cells showing only PP- or glucagon-like immunoreactivity are found too. In mouse stomach some endocrine cells showing only PP-immunoreactivity are demonstrated. In the same region coexistence of C-t-gastrin- and FMRF-amide-immunoreactivity is found in endocrine cells. The importance of these phenomena are discussed. Enteric nerves immunoreactive with antisera raised against substance P and GRP are found in mouse, against somatostatin and met-enkephalin in both mouse and fish and against VIP in fish.     

Immunocytochemical study of gastro-entero-pancreatic (GEP) endocrine cells in the vampire bat (Desmodos rotundus)

The distribution and frequency of gastro-entero-pancreatic (GEP) endocrine cells were studied in vampire bats by immunocytochemistry. Moderate numbers of somatostatin- and a few 5-hydroxytryptamine (5-HT)- and glucagon-immunoreactive cells were seen in the fundic cecum of the stomach. Numerous gastrin- and moderate numbers of somatostatin- and 5-HT-immunoreactive cells were found in the pyloric region. Moderate numbers of 5-HT-, somatostatin-, and gastrin-immunoreactive cells also were found in BRUNNER's glands. In addition to the above-mentioned 4 immunoreactive cell types, cells immunoreactive for glicentin, secretin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), and neurotensin were found in the intestine. Numerous insulin-, moderate numbers of somatostatin- and glucagon-, and a few 5-HT-immunoreactive cells were detected in the pancreatic islets with lesser numbers scattered within the exocrine pancreas. Motilin- and pancreatic polypeptide-immunoreactive cells were not observed in this study.     

Immunocytochemical identification and localization of peptide hormones in the gastro-entero-pancreatic (GEP) endocrine system of the mouse and a stomachless fish,Barbus conchonius

Summary A large number of antisera mainly raised against mammalian hormones are tested immunocytochemically on the GEP-endocrine system of mouse and fish (Barbus conchonius). The endocrine pancreas of mouse and fish appeared to contain the same four endocrine cell types; insulin-, glucagon-, PP- and somatostatin-immunoreactive cells.In mouse about 13 GEP endocrine cell types are distinguished 1. insulin-, 2. somatostatin-, 3. glucagon-, 4. PP-, 5. (entero)glucagon-/PP-like, 6. CCK-like, 7. substance P-, 8. neurotensin-, 9. VIP-, 10. gastrin-, 11. secretin-, 12. -endorphin-, 13. serotonin-immunoreactive cells.Based on this and a previous study at least 13 GEP endocrine cell types seems to be present in stomachless fish: 1–9 as described for mouse, 10. (entero)glucagon-like, 11. met-enkephalin, 12. VIP-like, 13. unspecific immunoreactive endocrine cells.Coexistence of glucagon and PP-like peptides is found in the gut and pancreas of mice and in the gut of B. conchonlus. In mouse pancreas and fish gut, endocrine cells showing only PP-or glucagon-like immunoreactivity are found too. In mouse stomach some endocrine cells, showing only PP-immunoreactivity are demonstrated. In the same region coexistence of C-1-gastrin-and FMRF-amide-immunoreactivity is found in endocrine cells. The importance of these phenomena are discussed.Enteric nerves immunoreactive with antisera raised against substance P and GRP are found in mouse, against somatostatin and met-enkephalin in both mouse and fish and against VIP in fish.In honour of Prof. P. van Duijn     

An immunohistochemical study on the distribution of endocrine cells in the gastrointestinal tract of the musk shrew, Suncus murinus

The endocrine cells in the gastrointestinal tract of the musk shrew were studied immunohistochemically. Eleven kinds of endocrine cells, immunoreactive for serotonin, somatostatin, gastrin, cholecistokinin, gastric inhibitory polypeptide, motilin, secretin, neurotensin, pancreatic glucagon, enteroglucagon and bovine pancreatic polypeptide, were revealed. In the stomach, serotonin-, somatostatin-, gastrin-, pancreatic glucagon- and enteroglucagon-immunoreactive cells were detected. The first three types of cells predominated and were more abundant in the pyloric glands than in the other stomach regions. In the small intestine, all types of endocrine cells were found, each having different distributions and relative frequencies. In the large intestine, 10 types of endocrine cells except cholecystokinin-immunoreactive cells were detected. Serotonin- and bovine pancreatic polypeptide-immunoreactive cells were more numerous in the large intestine than in the small intestine.     

Gastrointestinal hormones in birds: morphological, chemical, and developmental aspects

Historically, the enterochromaffin cell was the first endocrine cell type detected in avian gut; subsequently, a number of types of such cells were distinguished on the basis of the ultrastructural features of the secretory granules. More recently, immunocytochemical procedures have revealed somatostatin-, pancreatic polypeptide (PP)-, polypeptide YY-, glucagon-, secretin-, vasoactive intestinal peptide (VIP)-, gastrin-, cholecystokinin-, neurotensin-, bombesin-, substance P-, enkephalin-, motilin-, and FMRFamide-like immunoreactivity in avian gastrointestinal endocrine cells. Most endocrine cells are located in the antrum; there are a number in the proventriculus and small intestine but few in the gizzard, cecum, and rectum. Several avian gastroenteropancreatic hormones, including glucagon, VIP, secretin, bombesin, neurotensin, and PP, have been isolated and sequenced. They resemble the equivalent mammalian peptides in terms of molecular size but differ in amino acid composition and sequence; some (e.g., VIP) differ only in minor respects, others (e.g., secretin) more radically. Gastrointestinal endocrine cells appear late in development; available data indicate that few types are recognized by either immunocytochemistry or electron microscopy before 16 days of incubation. Experimental evidence has shown that at least the majority of gut endocrine cells are of endodermal origin and are not derived from the neural crest or neuroectoderm as earlier proposed. In early embryos, the progenitors of gastrointestinal endocrine cells are more widespread than are the differentiated cells in chicks at hatching. This, along with other observations, raises the question of factors that might influence the differentiation of gut endocrine cells.     

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.     

An immunohistochemical study of endocrine cells in the pancreas of the Red-bellied frog (Bombina orientalis)

The regional distribution and frequency of pancreatic endocrine cells in the red-bellied frog, Bombina orientalis, were studied by the immunohistochemical peroxidase anti-peroxidase (PAP) method using five types of specific mammalian antisera to insulin, glucagon, somatostatin, bovine pancreatic polypeptide (PP) and secretin. The frequency was calculated as the mean number of each endocrine cell type/1,000 total cells (including exocrine and endocrine cells) using an automated image analysis process. The percentage of each immunoreactive (IR) cell species to the total IR cell population was also calculated. In the pancreas of the red-bellied frog, all five endocrine cell types were demonstrated. Insulin IR cells were located in the pancreas as single cells or islet-like clusters. The latter were localized in central regions. The insulin-IR cells showed a frequency of 65.40 plus/minus 14.56/1,000 cells. Glucagon IR cells were also detected as single cells or as clusters but in the case of clusters, two distributional patterns were detected - a central core type and a marginally distributed type. They showed an abundance of 32.70 plus/minus 7.32/1,000 cells. Somatostatin-IR cells were dispersed throughout the pancreatic parenchyma as single cells, three to four cells, or clusters. The clusters were located in the marginal regions. The somatostatin-IR cell frequency was 19.40 plus/minus 6.52/1000 cells. PP-IR cells were randomly distributed throughout the pancreatic parenchyma as single cells with a frequency of 14.70 plus/minus 4.92/1,000 cells. Secretin-IR cells were demonstrated as clusters or as single cells, and as clusters they occupied the central regions. They showed a frequency of 39.60 plus/minus 10.36/1,000 cells. This is the first report of the presence of secretin-IR cells in amphibian pancreatic endocrine cells. Overall, there were 37.20 plus/minus 6.84% insulin-, 21.90 plus/minus 5.55% glucagon-, 11.60 plus/minus 4.33% somatostatin-, 8.60 plus/minus 2.72% PP- and 23.40 plus/minus 4.45% secretin-IR cells.     

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.     

The distribution and frequency of endocrine cells in the splenic lobe of grass lizard (Takydromus wolteri). An immunohistochemical study

The regional distribution and frequency of the pancreatic endocrine cells in the splenic lobe of grass lizard, Takydromus wolteri, were studied by immunohistochemical (PAP) method using six types of specific mammalian antisera against bovine Sp-1/chromogranin (bCG), serotonin, insulin, glucagon, somatostatin and human pancreatic polypeptide (hPP). The pancreas was subdivided into two regions--islet kike and exocrine regions. The frequency of each immunoreactive (IR) endocrine cells was calculated as mean number/total 100 islet cells and as mean number/total 1,000 cells (including exocrine and endocrine cells) using automated image analysis process. In addition, the percentage of each IR cell was also calculated. All of six endocrine cells were demonstrated. They were dispersed in the whole pancreatic parenchyma between exocrine acinar cells, or they were also observed as islet like clusters. In islet-like regions, bCG-, insulin- and glucagon-IR cells were detected as one or two cell layer cords and they were located between this cell-cords with 14.30+/-5.62, 61.50+/-9.76 and 26.50+/-9.31/100 cells frequencies, respectively. However, somatostatin-IR cells were mainly located in the peripheral parts not in cell-cords with 12.40+/-4.86/100 cells, and no serotonin- and hPP-IR cells were demonstrated. In exocrine regions, all of bCG-, serotonin-, insulin-, glucagon-, somatostatin- and hPP-IR cells were detected and they occurred mainly among the exocrine parenchyma as solitary cells with 10.30+/-2.54, 0.80+/-0.63, 15.50+/-5.30, 5.80+/-2.66, 3.10+/-1.29 and 11.00+/-3.33/1000 cells frequencies, respectively. In addition, serotonin-IR cells were mainly located between epithelia and connective tissue of pancreatic duct. Overall, there were 0.58+/-0.49% serotonin-, 56.44+/-9.35% insulin-, 23.73+/-8.22% glucagon-, 11.28+/-3.03% somatostatin- and 7.97+/-2.02% hPP-IR cells.     

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.     

Endocrine cells and nerves in the stomach of the lizard Podarcis hispanica detected by immunocytochemistry

The general identification of endocrine cells in the stomach of the lizard Podarcis hispanica was carried out by their response to the Grimelius and Masson-Fontana techniques. 11 immunoreactive cell-types, positive for chromogranin-, serotonin-, caerulein/gastrin/ cholecystokinin (CAER/G/CCK)-, glucagon-like-peptide-1 (GLP-1)-. glucagon-, bombesin-,somatostatin-, pancreatic polypeptide (PP)-, peptide tyrosine tyrosine (PYY)-, neurotensin-and calcitonin gene related peptide (CGRP)- antisera were detected by immunocytochemical methods. Co-existence of glucagon with GLP-1, and PP with PYY were observed in some cells. Furthermore, immunoreactivities for members of gastrin and PP families were also found to co-exist in a few cells. In the muscular layer, vasoactive intestinal peptide (VIP)- and substance P-immunoreactive nerve fibers were also found.     

An immunohistochemical study of gut endocrine cells in two species of insectivorous vespertilinid bats (Chiroptera: Pipistrellus abramus and Plecotus auritus sacrimontis)

11 endocrine cell types immunoreactive for either 5-hydroxytryptamine (5-HT), somatostatin, gastrin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), motilin, secretin, neurotensin, pancreatic glucagon, enteroglucagon or bovine pancreatic polypeptide (BPP) were found in gastrointestinal tract of 2 species of insectivorous bats. 5 of these 11 types of endocrine cells were located in the stomach and all 11 types of endocrine cells were found in the intestine. However, the distribution and relative frequency of each immunoreactive endocrine cell varied among the cell types and between the 2 species of bats examined. In Brunner's glands, gastrin- and 5-HT-immunoreactive cells were detected very rarely in Pipistrellus and only occasionally in Plecotus. The present results obtained from the insectivorous bats were compared with those of the sanguivorous vampire bats.     

An immunohistochemical study of the pancreatic endocrine cells of the Korean golden frog, Rana plancyi chosenica

The regional distribution and quantitative frequency of pancreatic endocrine cells were demonstrated in the Korean golden frog (Rana plancyi chosenica Okada), which is known as a Korean endemic species, for the first time, by immunohistochemical methods using specific mammalian antisera to insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). In the pancreas of the Korean golden frog, all four endocrine cell types were demonstrated. Insulin- and glucagon-positive cells were located in the pancreas as single cells or islet-like clusters with frequencies of 85.90±18.28 and 54.30±8.77/1,000/1,000 cells, respectively. Somatostatin-containing cells were also dispersed in the pancreas as single cells or clusters but in the case of clusters, they are exclusively situated in the marginal regions of insulin- or glucagon-positive cell clusters. Cells stained for somatostatin cell frequency was 15.50±3.10/1000 cells. PP-containing cells were also distributed as single cells or clusters with frequency of 53.40±11.96/1,000 cells. Clusters consisted of PP-positive cells are distributed as a core type and a marginally distributed type. Overall, there were 40.84±3.81% insulin-, 26.02±1.71% glucagon-, 7.63±2.09% somatostatin- and 25.51±3.26% PP-IR cells.     

Peptide hormone-like immunoreactivity in the gastrointestinal tract and endocrine pancreas of eleven teleost species

Summary The distribution of peptide hormone-like immunostaining in the gastrointestinal tract of 11 teleost species was investigated by immunofluorescence.Cells immunoreactive for somatostatin were found in the glandular epithelium of the stomach of four species and in the epithelium of the pyloric appendage of one species. The mid-gut epithelium contained cells reactive with antibodies to glucagon (three species), gastrin (five species), pancreatic polypeptide (five species), and substance P (two species). Cells immunoreactive for met-enkephalin were found in the epithelium of both the mid-gut and the stomach of six species.In six species in which the endocrine pancreas was investigated, insulin-, glucagon-, and somatostatin-like immunoreactivity was observed. Pancreatic polypeptide was definitely localised by immunostaining in cells of the endocrine pancreas of only one out of three species examined.Vasoactive intestinal polypeptide-, neurotensin-, bombesin-, and enkephalin-like immunoreactivity was identified in the gastrointestinal nerve fibres in various species.In view of the considerable species variation found, caution should be exercised in generalising about the peptides present in the gastrointestinal tract of fish.     

Immunohistochemical localization of some endocrine cells in the gastroenteropancreatic system of Erinaceus europaeus

The distribution of chromogranin A and neuron specific enolase (NSE) in the neuroendocrine gut system and the morphology and distribution of cells containing gastrin, somatostatin, neurotensin and VIP in the gastroenteropacreatic (GEP) apparatus of Erinaceus europaeus were investigated by immunohistochemical methods. Chromogranin A and somatostatin immunoreactive cells were present throughout the gastrointestinal mucosa, with the exception of the oesophagus and in the pancreas. Gastrin cells were peculiar of the pyloric glands and duodenal mucosa and neurotensin cells of the small intestine. No VIP immunoreactive endocrine cells were noticed in the GEP system. VIP and NSE immunoreactivities were detected both in nerve cell bodies and terminals of the wall of the GEP apparatus. NSE immunoreactivity was found in the endocrine cells of the fundic and pyloric mucosa.     

The endocrine pancreas of a squamate reptile, the desert lizard (Chalcides ocellatus). A histological and immunocytochemical investigation

The endocrine pancreas of the desert lizard (Chalcides ocellatus) was investigated histologically and immunocytochemically. The endocrine tissue was concentrated in the dorsal lobe, where it constituted about 7% of the total volume. In the ventral lobe the endocrine tissue formed approximately 1% of the total volume. Four endocrine cell types were observed in the pancreas of this species, namely insulin-, glucagon-, somatostatin- and pancreatic polypeptide (PP)-immunoreactive cells. The volume occupied by these cells was 1, 1, 0.6 and 0.3% of the total volume of the pancreas, respectively. Insulin-immunoreactive cells were located in the islet centre and comprised 3% of dorsal and 0.2% of the ventral lobe volume. Glucagon cells occurred at the islet periphery and amounted to 3 and 0.2% of the volume of the dorsal and ventral lobes, respectively. Somatostatin-immunoreactive cells were located at the islet periphery as well as in between the exocrine parenchyma. They constituted 1 and 0.2% of the volume of the dorsal and ventral lobes, respectively. PP-immunoreactive cells occurred mainly among the exocrine parenchyma as solitary cells. They formed only 0.03% of the volume of the dorsal lobe. The corresponding figure in the ventral lobe was 0.6%.     

Immunohistochemical study on the endocrine pancreas of cattle with special reference to coexistence of serotonin and glucagon or bovine pancreatic polypeptide

Bovine pancreatic endocrine cells were investigated by light microscopic immunohistochemistry. Serotonin-immunoreactive cells as well as insulin-, glucagon-, somatostatin-, bovine pancreatic polypeptide (BPP)-immunoreactive cells were detected in the pancreatic islets. Generally, insulin-immunoreactive cells were distributed throughout the islet and the others took peripheral location. Since the distribution and shape of serotonin-immunoreactive cells were very similar to glucagon- and BPP-immunoreactive cells, serial sections were restained by using the elution method. All glucagon- and BPP-immunoreactive cells also showed serotonin immunoreactivity but glucagon and BPP immunoreactivities were never observed to be colocalized in the same cell. A small number of serotonin-immunoreactive cells were observed that showed serotonin immunoreactivity only.     

Histological and immunohistochemical study on ontogeny of the endocrine cells in the quail gizzard

The pre- and post-hatching development and differentiation of the endocrine cells in quail gizzard were examined histologically and immunohistochemically. A total of 158 heads (from 5th d of incubation to adult) were used in this study. The formation of gizzard tubular glands began from 11th d of incubation. 8 kinds of endocrine cells, argyrophil cells, and gastrin releasing polypeptide (GRP)-, 5-hydroxytryptamine (5-HT)-, somatostatin-, glucagon-, avian pancreatic polypeptide (APP)-, neurotensin-, and gastrin-immunoreactive cells were detected in the gizzard. These endocrine cells began to appear from 10th d of incubation. Argyrophil cells and GRP-immunoreactive cells in the gizzard were increased with age. Other kinds of immunoreactive cells were found rarely and irregularly, and some of them were found transitory in the embryonic stage.     

New views on the identification of the various cell types in the pancreatic islets of the rat. An ultrastructural and morphometrical study

Islets of Langerhans taken from different parts of the pancreas have been studied ultrastructurally in adult rats. Five different islet cell types were identified in each islet with the aid of morphometrical analysis of their specific secretory granules. Previous immunohistochemical findings concerning the amount and location of insulin-, glucagon-, somatostatin- and pancreatic-polypeptide-containing cells and their ultrastructurally recognizable counterparts were compared, and it was possible to identify four main islet cell types with the electron microscope. Moreover, cells quite similar to the enterochromaffine cells described elsewhere in the exocrine pancreas and in the gastrointestinal tract were found to normally occur in the pancreatic islets of the rat.