Cellular Composition of the Pancreatic Islets in Mongolian gerbils (Meriones unguiculatus)

In Mongolian gerbil, morphological changes with age in the content of endocrine cells in the pancreatic islets were analyzed and their relation evaluated by an oral glucose tolerance test. The glucose level 2 hours after glucose administration was 125 ± 5 mg./dl in the young group and 103 ± 4 mg./dl in the old group. In the dorsal portion, B cells were mainly observed in the central area of the islets, surrounded by circular layers of A cells in the peripheral area. Between the A cells and B cells, D cells were scattered or present in layers. A few PP cells were present in the peripheral area of the islets. In the ventral portion, only a few A cells were observed in the peripheral area of the islets, and B cells were surrounded by PP cells. Secretory granules of A cells generally had an electron-dense spherical core in the limiting membrane. The halo between the limiting membrane and core in A cells was narrower than that in B cells. Secretory granules of B cells were larger than those in A cells, and the core was less electron-dense, and the halo was wider. Secretory granules of D cells were similar in size to those of A cells; the core showed low electron density, and the halo was very narrow. Granules of PP cells resembled those of A cells, but the electron density of the core was slightly lower. The gerbils showed changes in glucose tolerance, the size of the pancreatic islets, the percentage of B cells, and of A cells in the dorsal portion with age. The content of endocrine cells in Mongolian gerbils was similar to that in humans, rats, mice, and hamsters.     

Localization of amylin‐like immunoreactivity in the striped velvet gecko pancreas

Immunohistochemical techniques were employed to investigate the distribution of amylin‐like immunoreactive cells in the pancreas of gecko Homopholis fasciata. Four types of endocrine cells were distinguished: insulin immunoreactive (B cells), pancreatic polypeptide immunoreactive (PP cells), glucagon and pancreatic polypeptide immunoreactive (A/PP cells) and somatostatin immunoreactive cells (D cells). Pancreatic islets contained B, A/PP and D cells, whereas extrainsular regions contained B, D and PP cells. In the pancreatic islets, amylin‐like immunoreactive cells corresponded to B cells, but not to A/PP or D cells. In the extrainsular regions, amylin‐like immunoreactive cells corresponded to either B or PP cells. Amylin secreted from intrainsular B cells may regulate pancreatic hormone secretion in an autocrine and/or a paracrine fashion. On the other hand, amylin secreted from extrainsular PP and B cells, and/or intrainsular B cells may participate in the modulation of calcium homoeostasis in an endocrine fashion.     

An investigation of the relationship between duct system and A cell-rich and PP cell-rich pancreatic islets in the canine pancreas.

The pancreata of four six-month-old dogs of the same mother, two with both the pancreatic and accessory pancreatic ducts (X-type) and two with only the accessory pancreatic duct (Y-type), were examined in this study. To clarify the relationships between the type of pancreatic duct system and the composition of pancreatic endocrine cells, the pancreata were examined immunohistochemically using antiserum against four types of pancreatic hormones (glucagon, insulin, somatostatin and pancreatic polypeptide). In all areas of the X- and Y-type duct system pancreata, B cells accounted for 52-82% of the total number of islet cells, and D cells accounted for 4-15%. In the X-type ducts system, the percentages of A and PP cells in the right and left lobes of the pancreas differed greatly. It was found that A and PP cells appear in inverse proportion to each other and that there exist A cell-rich and PP cell-rich pancreatic islets. The A cell-rich pancreatic islets appeared in the left lobes along the accessory pancreatic duct, while the PP cell-rich pancreatic islets were observed in the right lobes along the pancreatic duct. The body of the pancreas contained both A cell-rich and PP cell-rich pancreatic islets. In the Y-type duct systems, A cell-rich pancreatic islets appeared in the right lobes. These findings indicate that the composition of A and PP cells in pancreatic islets is closely related to the type of duct system.     

Immunoreactivity of cytotoxic T-lymphocyte antigen 2 alpha in mouse pancreatic islet cells

Cells of the pancreatic islets produce several molecules including insulin (beta cells), glucagon (alpha cells), somatostatin (delta cells), pancreatic polypeptide (PP cells), ghrelin (epsilon cells), serotonin (enterochromaffin cells), gastrin (G cells) and small granules of unknown content secreted by the P/D1 cells. Secretion mechanism of some of these molecules is still poorly understood. However, Cathepsin L is shown to regulate insulin exocytosis in beta cells and activate the trypsinogen produced by the pancreatic serous acini cells into trypsin. The structure of the propeptide region of Cathepsin L is homologous to Cytotoxic T-lymphocyte antigen-2 alpha (CTLA-2 alpha) which is also shown to exhibit selective inhibitory activities against Cathepsin L. It was thought that if CTLA-2 alpha was expressed in the pancreas; then, it would be an important regulator of protease activation and insulin secretion. The purpose of this study was, therefore, to examine by immunohistochemistry the cellular localization and distribution pattern of CTLA-2 alpha in the pancreas. Results showed that strong immunoreactivity was specifically detected in the pancreatic islets (endocrine pancreas) but not in the exocrine pancreas and pancreatic stroma. Immunostaining was further performed to investigate more on localization of Cathepsin L in the pancreas. Strong immunoreactivity for Cathepsin L was detected in the pancreatic islets, serous cells and the pancreas duct system. These findings suggest that CTLA-2 alpha may be involved in the proteolytic processing and secretion of insulin through regulation of Cathepsin L and that the regulated inhibition of Cathepsin L may have therapeutic potential for type 1 diabetes.     

Immunohistochemical morphometry of pancreatic islets in the cat.

The application of immunohistochemical technique with antisera for glucagon (Glu), insulin (Ins), somatostatin (Som) and pancreatic polypeptide (PP) to serial sections of the cat pancreas permitted the quantitative evaluation of the population of 4 endocrine cell types and that of the area, larger diameter and density of islets. The pancreas was divided macroscopically into the 4 portions, duodenal, gastric, anastomotic and splenic. The duodenal portion was characterized by the localization of PP-immunoreactive (IR) cell-rich islets, the dissemination of PP-IR cells in the exocrine parenchyma and the absence of Glu-IR cells. In the duodenal portion, the area, the larger diameter and the density of islets were significantly smaller than those in the other 3 portions. On the contrary, the other 3 portions were marked with the deficiency of PP-IR cells and the existence of Glu-IR cell-rich islets. Ins-IR cells, identified as compact cell masses without any other types of cells, occupied a major part of every islet, composing much the same population throughout the 4 portions. The Som-IR cell population appeared to be closely in parallel with the Glu-IR cell population in all of the portions. It is concluded that all islets are similar in the Ins-IR cell population, but different in the complementary arrangement of Glu- and PP-IR cells. Based on this difference, 2 types of islets can be classified.     

Morphologic and immunocytochemical study of young dogs with diabetes mellitus associated with pancreatic islet hypoplasia

In 11 dogs (7 males, 4 females; 10 purebred, 1 mixed breed), diagnosed as having diabetes mellitus before the age of 6 months, the pancreas was evaluated histologically; in 6, the pancreas also was examined by use of electron microscopy and/or immunocytochemical methods. Each dog was placed in 1 of 3 groups (A through C) on the basis of pancreatic histopathologic findings: Group A (n = 3)--no recognizable islets, but the pancreas in 2 dogs contained scattered endocrine cells detectable by use of immunoperoxidase staining or electron microscopy; Group B (n = 4)--no recognizable islets, but the pancreas had severe vacuolation of ducts and acini, as well as acinar atrophy; Group C (n = 4)--scant shrunken islets; 1 pancreas had reduced numbers of recognizable islets, hydropic beta-cell vacuolation attributable to glycogen deposition, and islet and nonislet endocrine cells in expected proportions. Insulitis was not observed in any pancreas, although scattered lymphocytes were seen in the pancreatic interstitial fibrous tissue of 3 dogs. Histologic pancreatic lesions in these young dogs were distinct from those of type-I (insulin-dependent) diabetes mellitus in human beings, as well as from those of diabetes mellitus in aged dogs, but were similar to those described in other young diabetic dogs. This uncommon syndrome is distinct from commonly recognized canine diabetes mellitus, on the basis of age of onset, predisposition for purebred dogs, lack of predisposing endocrinopathies or obesity, and pancreatic histologic features. The cause(s) is unknown, but is related to pancreatic endocrine hypoplasia and not to insulitis or to exocrine pancreatic inflammation. The term pancreatic islet hypoplasia is chosen as best describing this disorder.     

鸭胰腺内高血糖素—,胰岛素—和生长抑素—免疫反应细胞的形态及分布

用ABC免疫组织化学方法,对1 周龄绍鸭胰腺内的高血糖素(A)、胰岛素(B)和生长抑素(D)免疫反应细胞的形态及分布进行了观察。结果表明,上述3 种细胞在全胰的分布及形态有差异。A 细胞主要成群散在于A 胰岛,少数位于混合型胰岛的边缘。D 细胞主要散在于A 胰岛中,少数位于B胰岛和混合型胰岛的边缘。B细胞主要呈团块状分布于B胰岛,少数位于混合型胰岛的中央。在胰外分泌部有散在的A 和D 细胞,位于腺泡及导管上皮细胞之间或结缔组织中。A 细胞形态各异,以多边形为主,多数细胞伸出形态多样的胞质突起,伸达胰岛或其他细胞间。D细胞的形态与A 细胞相似。B细胞形态均一,呈圆形或卵圆形,未见胞质突起,在外分泌部未见到B细胞。     

Immunohistochemical localization of chromogranin A in normal tissues from laboratory animals

To analyze the distribution of Chromogranin A in endocrine cells of various species of laboratory animals (dog, gerbil, guinea pig, hamster, monkey, mouse, and fetal, neonatal, and adult rats), normal tissues were stained immunohistochemically with polyclonal anti-bovine Chromogranin A antiserum (SP-1). Selected tissues (pituitary, adrenal, thyroid, parathyroid, pancreas, brain, peripheral nerve, stomach, small and large intestine, bone marrow, spleen, thymus, lymph node, and liver) from these species and from the rabbit were stained with two monoclonal anti-human Chromogranin A antibodies (LK2H10 and PHE5) to compare the immunoreactivities of the monoclonal antibodies and polyclonal antiserum. Staining with the polyclonal antiserum (SP-1) resulted in a broader spectrum of immunoreactivity but had more nonspecific background staining than either monoclonal antibody. Immunoreactivity and staining intensity with SP-1 varied between species, but most endocrine tissues (pituitary cells in the anterior and intermediate lobes, thyroid "C" cells, adrenal medulla, parathyroid, pancreatic islets, and enterochromaffin cells) from most species stained positively. In some species, pancreatic alpha cells stained more intensely, and two populations of adrenal medullary cells with different staining intensities were observed. Sciatic nerve (axonal area) was immunoreactive with monoclonal antibodies and/or the polyclonal antiserum in several species. The spectrum of immunoreactive tissues from fetal and neonatal rats increased with age. There was good cross-reactivity between species with SP-1, but not with either LK2H10 or PHE5. These results indicate that many endocrine cells with secretory granules in laboratory animals express Chromogranin A and that a polyclonal antiserum, such as SP-1, is more sensitive in detecting this protein in various species than monoclonal antibodies such as LK2H10 or PHE5.     

Immunocytochemical component of endocrine cells in pancreatic islets of horses

The endocrine cell components in the pancreatic islets of the following 4 pancreatic regions of the horse were investigated by immunohistochemical methods: lobus pancreatis sinister (left lobe); lobus pancreatis dexter (right lobe); and 2 regions of Corpus pancreatis (body), the duodenal lobe which lies along the cranial duodenal flexure and descending duodenum, and the intermediate lobe which is situated around the portal vein. The islets in the left and intermediate lobes contained a central mass of glucagon cells surrounded by insulin cells, a few somatostatin cells and sporadic pancreatic polypeptide (PP) cells. On the other hand, the islets in the duodenal lobe were small in size compared with the other 3 regions, and were predominant in insulin and pancreatic polypeptide (PP) cells, but almost lacked in glucagon cells. These findings suggested that the duodenal lobe was derived from the ventral pancreatic primordium, and the left and intermediate lobes were originated from the dorsal pancreatic primordium. In the right lobe, the composition and distribution of the islet cells were almost the same as those in the left and intermediate lobes, but there were several lobules containing numerous PP cells as seen in the duodenal lobe.     

Immunohistochemical studies on the splenic lobe of the pancreas in young Japanese quails (Coturnix c. japonica)

The splenic lobe (Lobus splenicus) of the pancreas of young meat-type quails (Coturnix c. japonica) was examined by immunohistochemical and light microscopic methods. The endocrine cells are mainly grouped as alpha, beta and mixed islets. A large region consisting of alpha cells is located in the central region of the splenic lobe whereas numerous beta islets are detected in the periphery of the splenic lobe. Alpha islets are in the majority composed of toluidine blue positive A cells and a few toluidine blue negative D and / or avian pancreatic polypeptide (APP) endocrine cells. Beta islets contain only a few toluidine blue negative B and a few D cells. Immunohistochemical staining of the splenic lobe reveal in the centre of beta islets numerous insulin immunoreactive cells and scarcely in alpha islets, exocrine tissue and / or among acinar cells. Somatostatin immune-reactive cells form a circular layer in the periphery of beta islets whereas these cells are uniformly distributed throughout the alpha islet parenchyma and exocrine tissue. In conclusion, the morphology but also the endo- and exocrine functions of the splenic lobe of quails are similar to observations in other avian species such as chicken, duck, goose and pigeon.     

光照对“星布罗”肉用仔鸡的生长发育及胰腺内分泌细胞结构和功能的影响

将72只日龄为14d的“星布罗”肉用仔鸡随机分为实验和对照两组,每组36只。实验组接受强度为151x的1L:3D间歇性白炽灯光照,对照组为自然光照。两组的饲喂条件相同。结果:与对照组相比,实验组体重略高而料肉比略低,实验组鸡胰腺A、B细胞的内分泌颗粒减少,A颗粒粒芯周围出现大致均匀的晕轮,B颗粒粒芯呈现不典型的针状、棒状或环状,PP细胞的内分泌颗粒明显增大、增多,胞浆中的粗面内质网、高尔基复合体和线粒体等数量增多。两组鸡的D细胞无明显差异。34日龄的实验组鸡血浆胰岛素含量明显高于对照组,且与体重呈正相关。     

Microanatomic features of pancreatic islets and immunolocalization of glucose transporters in tissues of llamas and alpacas

OBJECTIVE: To describe the microanatomic features of pancreatic islets and the immunohistochemical distribution of glucose transporter (GLUT) molecules in the pancreas and other tissues of New World camelids. ANIMALS: 7 healthy adult New World camelids, 2 neonatal camelids with developmental skeletal abnormalities, and 2 BALB/c mice. PROCEDURE: Samples of pancreas, liver, skeletal muscle, mammary gland, brain, and adipose tissue were collected postmortem from camelids and mice. Pancreatic tissue sections from camelids were assessed microscopically. Sections of all tissues from camelids and mice (positive control specimens) were examined after staining with antibodies against GLUT-1, -2, -3, and -4 molecules. RESULTS: In camelids, pancreatic islets were prominent and lacked connective tissue capsules. Numerous individual endocrine-type cells were visible distant from the islets. Findings in neonatal and adult tissues were similar; however, the former appeared to have more non-islet-associated endocrine cells. Via immunostaining, GLUT-2 molecules were detected on pancreatic endocrine cells and hepatocytes in camelids, GLUT-1 molecules were detected on the capillary endothelium of the CNS, GLUT-3 molecules were detected throughout the gray matter, and GLUT-4 molecules were not detected in any camelid tissues. Staining characteristics of neonatal and adult tissues were similar. CONCLUSIONS AND CLINICAL RELEVANCE: In New World camelids, microanatomic features of pancreatic islets are similar to those of other mammals. Data suggest that the poor glucose clearance and poor insulin response to hyperglycemia in adult camelids cannot be attributed to a lack of islet cells or lack of GLUT molecules on the outer membrane of those cells.     

Histogenesis of neoformation in the endocrine pancreas of aging horses

Pancreatic tissue from 20 horses was examined using immunocytochemical techniques. In aged horses, neogenesis of endocrine cells, neoformation, and hyperplasia of islets occurred closely associated with the pancreatic duct; these changes were regarded as nesidioblastosis. In addition, pancreatic fibrosis accompanied by ductal proliferation and endocrine neogenesis was considered a regenerative change. Thus, the origin of neoformation in the endocrine pancreas was in the ductal system, and it is suggested that the pancreatic endocrine cells were of endodermal origin.     

Impaired pancreatic endocrine and exocrine responses in growth-retarded piglets

The alteration of pancreatic endocrine and exocrine secretory responses induced by secretagogues and neural input was investigated in post-weaning growth-retarded (GR) piglets. Blood and pancreatic juice were collected from these animals (6-8-weeks old). Plasma insulin and pancreatic digestive enzymes induced by nutrients, drugs and vagal stimulation were measured biochemically. The pancreas was inspected by immunohistochemical analysis. In GR piglets, the plasma glucose and insulin concentrations at the resting state were very low, and the secretory response was also markedly reduced, with maximum inhibition of 90% by glucose administration and 83% by arginine administration. The insulin secretion was not increased by 2-deoxy-D-glucose administration in GR piglets. The pancreatic juice secretions induced by vagal stimulation and secretagogues in GR piglets were not different from those induced in the control piglets. However, amylase activity in the pancreatic juice and in the pancreas was significantly decreased in GR piglets, although trypsin and chymotrypsin activities were not different. In the immunohistochemical analysis, the numbers of islets and the staining degree for insulin antibody also declined in the pancreases of GR piglets. These results indicated the reduction of insulin and amylase secretions from the pancreas in GR piglets, suggesting that a dysfunction of pancreatic endocrine and exocrine secretion during growth after weaning may be an important factor in the induction of growth retardation in piglets.     

绍鸭胰腺胰高血糖素免疫反应细胞生长发育的显微图像分析

用免疫组织化学ＡＢＣ法，显示绍鸭胚发育期间胰内高血糖素细胞，观察Ａ细胞的形态及分布；用显微图像分析仪测定Ａ细胞的积分光密度值；并求各时期Ａ细胞的平均积分光密度值，再作统计学分析。结果表明：Ａ细胞形态多样，但以多面形为主，并上侈种形式的胞 质突起。本文显示了胰腺Ａ细胞在胚后发育期间的发变化规律。为胃肠胰内分泌系统的功能研究提供动态变化的基础资料。     

Expression of the sweet receptor protein, T1R3, in the human liver and pancreas

The expression of T1R3, a taste receptor essential for the perception of sweetness and umami-taste, was examined by immunohistochemistry to determine whether and where it may be localized in the liver and pancreas. In the liver, both immunopositive and immunonegative reactions were detected; bile ducts and intercalated portions of the bile ductules were immunopositive to T1R3, while arterioles and venules were immunonegative in interlobular connective tissue. In the hepatic lobule, all other cells including liver cells (hepatocytes) and bile capillaries were immunonegative. In the pancreas, all endocrine portions of the pancreas were immunonegative to T1R3. Within the exocrine portions, immunopositive reactions were detected in excretory duct cells, intercalated cells, and centroacinar cells. In contrast, acinar cells were immunonegative, as were vessels, lymph capillaries, nerve fibers, and connective tissue cells in the exocrine portions. The restricted localization of T1R3 in the duct cells of the liver and pancreas in the present study may indicate that T1R3 is involved in monitoring changes in the makeup of bile and pancreatic juices in the hepatic and pancreatic duct systems.     

Histopathological Changes in the Pancreas from a Spontaneous Hyperglycemic Cynomolgus Monkey

Morphological and immunohistochemical examinations were carried out on the pancreas of a hyperglycemic 5-year-old male cynomolgus monkey. Body weight gradually decreased from 6 months before termination, accompanying a slight reduction in food consumption and anorexia for the last 2 days. The blood glucose level was markedly elevated when examined at termination. Histopathologically, in the exocrine pancreas, diffuse hyperplasia of centroacinar and intercalated duct cells and diffuse atrophy of acinar cells with sporadic apoptosis were observed, although most centroacinar and intercalated duct cells were proliferating cell nuclear antigen (PCNA)-positive in both the present case and age-matched control animals. In the endocrine pancreas, the islets tended to be hypertrophic, with an increase in insulin-positive cells in comparison with the age-matched control animals. PCNA-positive cells also tended to increase in the islets, although positive cells for phospho-histone H3, a marker for mitotic cells, were not detected in the endocrine and exocrine pancreas. Moreover, neither inflammation nor amyloidosis was noted in the islets. In conclusion, the present case probably suffered from early-stage type 2 diabetes mellitus, and it provides fundamental information concerning pancreatic histopathology under insulin-related derangement in monkeys.     

Ultrastructure of pancreatic alpha and beta cells in young quails (Coturnix coturnix japonica) fed aflatoxin

The present investigation was undertaken to assess the effects of aflatoxin (AF) containing diets on alpha and beta cells of the endocrine pancreas in young quails by means of light and electron microscopy. A total of thirty quails were divided into 3 groups, each comprising 10 animals. Total AF was incorporated into the diet of these groups, at dosages of 0 (control, group 1), 2.5 (group 2), and 5.0 (group 3) mg AF/kg feed. The chicks were housed in electrically heated battery cages and exposed to light for 24 h from hatching to 3 weeks of age. Quails consumed the diets and water ad libitum. Electron microscopic examinations demonstrated degranulation of alpha cells, decrease in the size and number of secreting granules, and increase in the number of free ribosomes and polisomes in the animals of group 2 and 3. In beta cells, the numbers of free ribosomes and polisomes decreased, whereas the number of mature granules increased in the animals of group 3. Mononuclear cell infiltrates were observed in the periphery of capillaries and around endocrine islets in the experimental groups. Furthermore, capillaries of the animals in group 2 and 3 were dilated at all sides of both alpha and beta islets. According to the results of this study, the addition of aflatoxin to the diets of quails at dosage of 2.5 and 5 mg AF/kg leads to significant changes in pancreatic alpha and beta cells. These changes may exhibit adverse effect on the metabolism of carbohydrates in poultry.     

Development of the chick pancreas with regard to estimation of the relative occurrence and growth of endocrine tissue

Endocrine cells in chick pancreas were observed to map their distribution during development and to perform morphometric studies starting on embryonic day 5. The ratio of exocrine to endocrine tissues first prevailed in favour of the endocrine ones, and changed abruptly after day 9 when rapid growth of exocrine tissue began. Endocrine tissue was formed of two types of islets. The 'light' (or B) islets were composed of insulin-immunoreactive cells, completed perhaps by a few somatostatin-immunoreactive cells occurring on the periphery. The majority of the somatostatin- and glucagon-immunoreactive cells were present in the 'dark' (or A) islets. Endocrine elements were also scattered as single cells over the pancreas. Sporadically, the endocrine cells established contacts with exocrine ducts. In morphometric analysis, volume density of insulin-, glucagon-, and somatostatin-immunoreactive cells was measured, and ratios were calculated between particular components. The volume density of endocrine cells and their ratio appeared stable in individual lobes but varied significantly between each other. Increase of the glucagon volume density is exponential, whereas insulin increases almost linearly especially in splenic lobe. The process results in the increase of the hormone-immunoreactive cell volume density in favour of glucagon-immunoreactive cells typical for birds.     

An Immunohistochemical Survey of Catecholamine-synthesizing Enzyme-immunoreactive Nerves and Endocrine Cells in the Bovine Pancreas

The distribution of catecholamine-synthesizing enzyme-immunoreactive nerves and endocrine cells in the pancreas of the calf and cow was studied immunohistochemically using antisera against tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). TH- and DBH-immunoreactive nerve fibres were abundant both within and around the islet of Langerhans. A few TH- and DBH-immunoreactive nerve fibres were seen around the large islets characteristic of calf pancreas, but the majority of cells in the large islets, and some in islets of Langerhans, showed TH immunoreactivity. In the exocrine pancreas, both TH- and DBH-immunoreactive nerve fibres were distributed randomly among the acini, with the DBH-immunoreactive fibres being more numerous. Abundant TH- and DBH-immunoreactive nerve fibres were seen in close association with blood vessels and in the connective tissue around the interlobular duct. Immunoreactivity for both enzymes was also observed in the nerve cell bodies and fibres of the intrapancreatic ganglia. The findings suggest an important role for catecholamines in the regulation of bovine pancreatic function.