Splenic Lobe Research Articles

Morpho-structural Study of the Pancreas and Pancreatic Duct in Ostrich (Struthio camelus L.)

The peculiarity of the digestive process in ostrich and the lack of bibliographic data on the pancreas and its excretory system in this species led us to undertake macroscopical and histological investigations to explore possible differences compared to other avian species. Our findings demonstrated the presence of two pancreatic lobes, dorsal and ventral, and a third lobe, the splenic lobe, detectable only histologically. The most interesting data concerned the number, course, drainage and structural peculiarities of the pancreatic duct. The structural and ultrastructural features of the two cell types lining the pancreatic duct (main cells and globose cells) were suggestive of their role in secretion and resorption of the pancreatic juice. The results allow the understanding of the particular digestive process of this species.

Intra-Arterial Instillation of Microencapsulated, Ifosfamide-Activating Cells in the Pig Pancreas for Chemotherapeutic Targeting

Background: The therapeutic efficacy of intratumoral instillation of genetically engineered, CYP2B1-expressing, microencapsulated cells in combination with ifosfamide had been previously demonstrated in xenografted human pancreatic ductal carcinomas [Gene Ther 1998;5:1070–1078]. Prior to a clinical study, the feasibility of an intra-arterial application of microencapsulated cells to the pancreas and its consequences to the organ had to be evaluated. Material and Methods: Microencapsulated, CYP2B1-producing cells were instilled both in vivo (transfemoral angiographical access) and in vitro (perfusion model) in the splenic lobe of the pig pancreas. In vivo, animals were monitored clinically for 7 days, then treated with ifosfamide and sacrificed. In vitro, ifosfamide was administered intra-arterially. Results: In all animals, 100 microcapsules could be instilled safely via the femoral route without clinical, biochemical or histological signs of pancreatitis. Histological examination revealed partial obstruction of small arteries by the capsules, without causing any parenchymal damage. In vitro, instillation reduced blood flow by half. Ifosfamide, also in combination with the capsules, did not add any damage to the pancreas. Conclusion: Intra-arterial instillation of microencapsulated cells to the pig pancreas is feasible and safe. Neither pancreatitis, foreign body reactions nor circulatory disturbances were observed. Clinical application of this genetically enhanced chemotherapeutic method seems possible.

Effects of acetylcholine on A and B cells of the lizard endocrine pancreas

The effects of acetylcholine (ACh) administration on the endocrine pancreas of the lizard Podarcis sicula were studied by histological and immunocytochemical methods at light and electron microscopy, and in situ hybridization, and the results were evaluated by image analysis. In control lizards, the endocrine islet cells, especially B cells, displayed heterogeneity in the immunoreactive content of secretory granules in both the splenic and duodenal pancreatic lobes; however, this feature was more evident in the former. Following ACh administration, the differences in B cells between the splenic and duodenal lobes were more marked. In fact, splenic lobe B cells showed a bubbling aspect caused by a massive exocytosis testified by the greatly swollen ß secretory granules devoid of their content. The duodenal lobe B cells exhibited images of exocytosis to a lesser extent and ‘disorganized’ granules. The secretion of A cells was also stimulated by ACh. These morphological observations were supported by optical density of immunostaining, cell surface areas, granular size, and labeling density measurements of B and A cells carried out using the Ks 300 image analysis system, which showed a reduction of these parameters in the treated lizards. In situ hybridization with proinsulin and proglucagon probes revealed that ACh stimulated not only release but also synthesis of insulin and glucagon, as can also be seen from the enlarged RER cisternae and Golgi complexes of B and A cells.

Histopathologic Changes Induced by Cellophane Wrapping of the Pancreas Are Unaffected by Cigarette Smoke Exposure in Hamsters

This study tests whether exposure to cigarette smoke alone or combined with cellophane wrapping of the pancreas increases the development of microscopic abnormalities in the pancreas of Syrian golden hamsters. Ninety hamsters were randomly divided into 4 groups. Thirty-five hamsters were exposed to 3 continuous hours of cigarette smoke daily for 3 months following celiotomy to cellophane wrap the gastric lobe of the pancreas (group 1). Thirty-two hamsters were not exposed to continuous cigarette smoke and had the wrap surgery alone (group 2). Twelve hamsters were exposed to cigarette smoke and had no surgery (group 3). Eleven hamsters had no exposure to cigarette smoke and no surgery (group 4). All of the hamsters were sacrificed after 3 months. The gastric (wrapped) and splenic (unwrapped) lobes of the pancreas were reviewed grossly and histologically. In all 4 groups, there were no gross abnormalities in either lobe of the pancreas. Histopathologic evaluation of the gastric lobes from group 1 showed that 13 of 35 lobes (37%) had pancreatitis (11 chronic, 1 acute, and 1 both). In group 2, 12 of 32 (38%) gastric lobes had pancreatitis (10 chronic, 2 acute). The incidence of pancreatitis in groups 1 and 2 was significantly higher than in groups 3 (0/12; p < 0.04) and 4 (0/11; p < 0.03), respectively. A significantly lower incidence of pancreatitis was found in the splenic lobes of all 4 groups when compared to gastric lobes in groups 1 and 2. Three of the 67 cellophane-wrapped glands had ductal hyperplasia. The effects of cellophane wrapping of the pancreas, both in the wrapped and unwrapped areas, induced changes of pancreatitis and hyperplasia that may be preneoplastic. Cigarette smoking, alone or combined with cellophane wrapping, did not cause these changes. Longer exposure to cigarette smoke may be needed to cause premalignant changes in the hamster pancreas.

Apoptosis of acinar cells is involved in chronic pancreatitis in Wbn/Kob rats: role of glucocorticoids.

The involvement of pancreatic acinar cell apoptosis and its relation to glucocorticoid exposure were investigated in spontaneously occurring chronic pancreatitis in male Wistar Bonn/Kobori (WBN/Kob) rats. Although most lobules were not inflamed in 10-week-old WBN/Kob, increased apoptosis of pancreatic acinar cells, confirmed by TUNEL staining was focally observed (0.10 +/- 0.10 vs. 0.05 +/- 0.10/field in 10-week Wistar rats). Localized hemorrhagic lesions and brown foci in the splenic lobes were apparent, with significant decrease in pancreas weight in 20-week WBN/Kob rats along with marked apoptosis (1.95 +/- 0.31 vs. 0.07 +/- 0.04/field in 20-week Wistar rats). Electron microscopy revealed apoptotic bodies to be present in acinar cells. Pancreatic myeloperoxidase activities, indirect indices of granulocyte infiltration, as well as histologic scores were significantly increased at 15 and 20 weeks, and endogenous corticosterone levels were significantly decreased at 10, 15, and 20 weeks as compared with values for age-matched Wistar rats. Prednisolone in the drinking water (0.01 mg/mL; calculated dose, 1.03 0.03 mg/kg/d) for 10 weeks significantly attenuated increases in numbers of apoptotic acinar cells and pancreatic myeloperoxidase activities and tended to reduce the histologic scores in 20-week WBN/Kob rats as compared with the vehicle group. In summary, (a) apoptosis of pancreatic acinar cells is involved in chronic pancreatitis, (b) endogenous corticosterone is decreased, and (c) prednisolone treatment attenuates both apoptosis of pancreatic acinar cells and chronic pancreatitis in male WBN/Kob rats. We conclude that apoptosis of acinar cells related to decreased corticosterone may be a trigger of chronic pancreatitis in this model.

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.

Endocrine Pancreatic Cells fromXenopus laevis:Light and Electron Microscopic Studies

Insulin, glucagon, pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), somatostatin (SST)-28 (1-12), salmon (s) SST-25, and SST-14 immunoreactivities were demonstrated in the pancreatic endocrine cells ofXenopus laevisusing light and electron microscopic immunocytochemistry. Insulin-, SST-28 (1-12)/SST-14-, and PYY-immunoreactive (ir) cells were found throughout the pancreas either isolated in small clusters of a single cell type or, except in the case of PYY-ir cells, forming islets consisting of various cell types. Anti-sSST-25 serum detected the invariant SST-14 form. Cells that were only immunoreactive to glucagon were isolated or clustered in the duodenal lobe, while in the splenic lobe cells immunoreactive to both glucagon and PP were observed in isolation, clustered, or in the periphery of the islets. There were no cells that were immunoreactive only to PP or to NPY. Ultrastructurally, the endocrine cells were characterized by their secretory granules, which were immunogold labeled with the corresponding antisera. Insulin cells had large round secretory granules with a round, irregular, or crystalline-like dense core. Glucagon-ir cells had round secretory granules with a dense core and a clear halo. Glucagon/PP- and PYY-ir cells showed round, ovoid, or pear-shaped secretory granules, which were larger and less electron dense in the latter cell type. The secretory granules of SST-ir cells were ovoid or bacillary with a medium electron-dense content. A sixth cell type with very small secretory granules could only be characterized by conventional electron microscopy, since it did not immunoreact with any of the antisera applied in this study.

Critical islet mass for successful porcine islet autotransplantation.

A major reason for the failure of clinical islet transplantations may be a limited islet mass. The aim of this study was to determine the critical islet mass necessary for normalization of glucose metabolism in a porcine model. Diabetes was induced by total pancreatectomy. The splenic lobe of the pancreas was intraductally distended with UW-solution containing 2.67-3.33 mg/ml collagenase, and the distended pancreas was digested in a continuous digestion filtration device. The islets were purified on a isoosmotic Ficoll-sodium-diatrizoate gradient. The survival period of the diabetic recipients in group 2 and 3 receiving, respectively, a low (2.14+/-0.39 microL/kg body weight) and a high (4.99+/-0.83 microL/kg body weight) islet mass was significantly prolonged compared to that of diabetic recipients in group 1 receiving no islet transplantation. However, the survival period of the recipients in group 2 was not significantly different to that in group 3. Three recipients of an islet mass of >5 microl/kg body weight became normoglycemic (fasting blood glucose <100 mg/dl) for more than two months. Furthermore, the glucose and insulin release reactions to the glucose challenge were comparable to that before pancreatectomy. Contrarily, another five diabetic recipients of an islet mass of <4 microL/kg body weight became a fasting blood glucose level of <200 mg/dl. The glucose and insulin release reactions to the glucose challenge were improved only, but not normalized compared to that before pancreatectomy. The data presented in this study demonstrate that metabolic normalization in pancreatectomized diabetic minipigs can be established by autotransplantation of an islet mass of >5 microl/kg body weight.

Morphogenesis and differentiation of the avian endocrine pancreas, with particular reference to experimental studies on the chick embryo.

The avian pancreas has three or four lobes and develops from a dorsal and two ventral buds. The cells that will contribute to formation of the dorsal bud are at first located in the mid-dorsal endoderm, those of the ventral buds in the floor of the foregut. The determination of endoderm to form dorsal and ventral bud derivatives occurs before formation of the buds. The highest concentration of endocrine tissue is in the splenic lobe. The lobes contain A and B islets in which glucagon and insulin cells, respectively, predominate. Islets contain somatostatin and pancreatic polypeptide (PP) cells, both of which also occur scattered in the exocrine parenchyma. Pancreatic endocrine cells arise from endoderm: glucagon, insulin, and somatostatin cells differentiate early, PP cells later. To establish culture conditions suitable for avian insulin cells, the epithelial component of dorsal buds of 5-day chick embryos was cultured under various conditions. At the end of 7 days the proportion of insulin cells was determined. In raising the proportion of insulin cells, Matrigel was superior to collagen gel and a serum-free medium (incorporating insulin, transferrin, and selenium) was superior to a serum-containing medium. Modifications to the serum-free medium were tested. Raising the level of glucose or of glucose and essential amino acids increased the proportion of insulin cells. This proportion was also increased by replacement of insulin by insulin-like growth factor-I, whereas addition of transforming growth factor beta1 reduced the proportion. Transfer of explants from poor to favourable culture conditions showed that the improved conditions stimulated quiescent insulin progenitor cells to develop.

A new model for pancreatitis.

Pancreatitis induced by ligation of the pancreatic duct produces morphologic similarities to human pancreatitis. This model is easily performed in big animals, but it is very difficult to perform pancreatic duct ligation in small animals. Many experimental studies of pharmaceutical treatments for pancreatitis used pancreatic duct-ligation models, but it is also difficult to evaluate the efficacy of the drugs used, because the animals used are of different species with individual differences. To overcome these problems, we ligated the main pancreatic duct of the splenic lobe by a 5.0 absorbable suture by using a surgical microscope and left the gastroduodenal lobe intact in the same rats. This model produced damaged pancreatic tissue in one part and normal pancreatic tissue in another part of the pancreas in the same animals, biochemically and histologically. We evaluated the effect of a new protease inhibitor (ONO-3404) on this preliminary model and found this new protease inhibitor demonstrated a hypertrophic effect on the damaged pancreatic tissue and the normal pancreatic tissue in the same animals. This model is also useful to study pharmaceutic treatment for pancreatic insufficiency and to study chemically induced pancreatic carcinogenesis in the damaged pancreatic tissue and the normal pancreatic tissue in the same animals.

Afferent innervation of the rat pancreas: retrograde tracing and immunohistochemistry in the dorsal root ganglia.

This study was undertaken to determine the segmental organization of the dorsal root ganglion (DRG) cells that give rise to pancreatic afferents containing a certain neuropeptide in the rat. These cells were examined using retrograde tracing combined with immunohistochemistry. Injection of horseradish peroxidase (HRP) into the pancreas resulted in the labeling of cells in bilateral T5-L2 DRGs, with most labeled cells lying at T10-T11. Injection into the duodenal (right), splenic (left), and entire lobes consistently produced more labeled cells significantly in the right, left, and right DRGs, respectively. Calcitonin gene-related peptide (CGRP)-, substance P (SP)-, somatostatin (SOM)-, and galanin (GAL)-immunoreactive (IR) cells in the DRGs (T9-T12) were found in -52, 17, 8, and 6%, respectively, but neuropeptide Y- and vasoactive intestinal polypeptide-IR cells were not found. About 88% of HRP-labeled cells in DRGs (T9-T12) contained CGRP, and approximately 16% of them contained SP. Although SOM- and GAL-IR cells were localized in the DRGs, these cells innervating the pancreas could not be found. In brief, these results show that bilateral (not similar in cell number on each side) DRG cells innervate the duodenal or splenic pancreas, and the majority of these cells that project to the pancreas contain CGRP and SP.

Somatostatin-14 and somatostatin-28 in chicken pancreatic islet D-cells

Somatostatin (SST)-14 and mammalian (m) SST-28 [1–14] immunoreactivities of chicken pancreatic islets were investigated by using light microscopic immunohistochemistry. Chicken D-cells in both A- and B-islets showed immunoreactivity to SST-14, but not to mSST-28 [1–14]. The acid-extract from both splenic and ventral lobes of pancreas was fractionated by reverse-phase high-performance liquid chromatography, and the SST-like immunoreactivity was measured in the radioimmunoassay using anti-SST-14 serum. In both lobes, the SST-like immunoreactivity was detected in the fraction which corresponded to that of SST-14 standard, but was not found in that of mSST-28 standard. Immunohistochemically, pancreatic endocrine D-cells of 1 amphibian, 4 reptiles and 12 birds showed the same immunostaining property as chicken D-cells. By contrast, both SST-14- and mSST-28 [1–14]-immunoreactive D-cells were observed in the pancreatic islets of 16 mammals. From these results, we concluded that chicken islet D-cells contain only SST-14-like peptide, but not SST-28-like peptide, and that this phenomenon may be common to the avian species.

Pancreatic regeneration ( reg) gene expression in a rat model of islet hyperplasia

After pancreatectomy, regeneration of acinar and islet elements occurs. Recent data from a model of islet hyperplasia in the hamster suggested that induction of a local pancreatic factor stimulates islet formation. We postulate that the reg gene may be this factor. We studied reg expression during induction of islet growth by using a similar model in the rat. Rats underwent surgical wrapping of the splenic lobe of the pancreas or sham operation. At 2 days ductular proliferation and immunohistochemical evidence of insulin within ductular epithelia were evident in the wrapped lobe. By 14 and 56 days islet number per square millimeter increased 63% and 43%, respectively. Reg mRNA levels, measured by Northern blot analysis with a rat reg cDNA probe (n = 5), increased 300% at 2 days in the wrapped lobe and decreased to that of unwrapped controls by 14 days. In situ hybridization showed localization of reg to the acinar cells. In unwrapped gastric lobes of animals who underwent surgical wrapping of the splenic lobe, no change in islet number per square millimeter or reg gene expression was noted. Surgical wrapping of the pancreatic splenic lobe induces local reg gene expression that is temporally associated with duct cell hyperplasia. This is followed by islet formation within the wrapped lobe. Reg may play a role in the induction of new islets from ductular precursors and in maintenance of normal islet function.

Anatomy of vasculature of 850 spleen specimens and its application in partial splenectomy

Anatomic knowledge of vasculature of the splenic lobe and segment is of great clinical significance in partial resections and transplantation of the spleen. The methods of two-colored corrosion casting, roentgenography, and anatomic dissection were used to evaluate the vasculature of the splenic hilum and intraspleen. On this basis splenic lobectomy and segmentectomy were performed on 42 patients with traumatized spleens. In the observation of 850 spleen specimens the spleen showed a single lobar artery in 7 cases (0.8%), two lobar arteries in 730 cases (86%), three lobar arteries in 104 cases (12.2%), and multiple lobar arteries (i.e., more than three lobar arteries) in 9 cases (1%). In a subgroup of 276 specimens 17%, 53%, 24%, 4%, 1%, and 1% of spleen specimens had three, four, five, six, seven, and eight segmental arteries, respectively. The result from a subgroup of 280 specimens indicated that mean percentages of the existence of the superior and inferior polar arteries and of the coexistence of both polar arteries were 31.3%, 38.8%, and 13.3%, respectively. Relative avascular planes between segments or lobes were seen. Basic steps of splenic lobectomy or segmentectomy include mobilization of the injured spleen, ligation of vessels in the lobe or segment, transection of the splenic parenchyma, and sutures of the cut surface of the remaining spleen. The postoperative courses of all 42 patients undergoing partial splenectomy were uneventful. No postoperative bleeding and necrosis of the remaining spleen or infectious complications were registered. Anatomically the spleen is defined with two primary lobes (the superior lobe and inferior lobe), one accessory lobe, and three to five segments. This new classification facilitates surgeons to perform partial resections of the spleen and allotransplantation of the hemispleen from a living related donor in human beings.

Studies of the isolation, viability, and preservation of purified islets after surgical pancreatectomy in large pigs

Abstract: Previous studies have shown separation of mass quantities of islets from slaughterhouse pig pancreases. In these studies, we examined the isolation, viability, and preservation of pig islets obtained by surgical pancreatectomy. Pigs aged 6 to 30 months weighing 100 to 200 kg were subjected to laparotomy under general anesthesia. The splenic lobe of pancreas was mobilized without warm ischemia. Islets were immediately isolated by collagenase perfusion through the duct, automated dissociation, and Ficoll purification. Yields of islets (150 μm size) were 8500 to 9300/g for two different collagenases before purification. Purification yielded 90% pure islets, but yields decreased to 400 to 600/g. Perifusate insulin release was biphasic after glucose/theophylline with 3 to 5‐fold stimulation. Following culture/cryopreservation marked islet losses occurred but viability was preserved. Quantities of 1,500 islet equivalents resulted in euglycemia in nude mice. These data show that mass quantities of viable islets can be isolated after pancreatectomy, but there is marked islet loss during purification and subsequent preservation due to inherent islet fragility.

Changes in the mouse exocrine pancreas after pancreatic duct ligation: a qualitative and quantitative histological study.

The pancreatic duct from the splenic lobe, the largest lobe of the pancreas in the mouse, was ligated at 6 weeks of age, with histological and cytological changes in the organ examined 1 day to 16 weeks after the ligation. Changes in the volumes of the pancreatic lobe, exocrine tissue, and interstitial tissue as well as relative total numbers of each cellular element in the organ after duct ligation were stereologically obtained using serial sections of the whole pancreas. Cell sizes, degenerated cell and mitotic cell indices, and nuclear densities of the acinar and ductal cells were also obtained. After duct ligation, the volume of the pancreas increased by interstitial edema in the first 2 days but rapidly decreased thereafter due to atrophy of the exocrine tissue, amounting to 10% or less of normal volume by 7 days. The acinar cells showed an accumulation of the zymogen granules, cytoplasmic condensation and a pyknotic figure of the nucleus; they then were thoroughly deleted with appearance of numerous macrophages. This cell death was suggested to be due to apoptosis. On the other hand, the ductal cells remained in the atrophic pancreas and proliferated with mitotic figures to two times the normal frequency at 3 days, and then formed duct-like structures lacking in the acinar cells. After 2 week, the ductal cells slowly decreased in number also due to cell death, but the pancreas became gradually enlarged by intralobular fatty replacement, to reach a volume approximating that of normal 8 weeks after duct ligation. The stereological method serves for the correct evaluation of cell dynamics including the deletion and proliferation of the cells in the whole organ.

Apoptosis of mouse pancreatic acinar cells after duct ligation.

It has been established that pancreatic exocrine acinar cells disappear after pancreatic duct obstruction. This study aimed to examine the relationship between the disappearance of the acinar cells and apoptosis after pancreatic duct ligation of the splenic lobe in dd-mice, six weeks of age. In some mice, the ligature was removed after two or three days. In addition to general light and electron microscopic examinations on the pancreatic tissues, paraffin sections stained with the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method were observed to detect nuclear DNA fragmentation. Pancreatic acinar cells underwent apoptosis initiated with nuclear DNA damages three days after duct ligation and were completely deleted by seven days. Due to the elevation of the intraluminal pressure, the acinar cells showed interrupted secretion of their zymogen granules and disorganization of their rough endoplasmic reticulum, causing the cessation of granule formation before apoptosis started. These cytoplasmic changes prior to apoptosis are reversible, as observed after removal of the ligation. Apoptosis of the acinar cells was indentified by TUNEL-labeling of the nuclei, the condensation and margination of nuclear chromatin, and round fragmentation of cell bodies, all irreversible changes. Apoptosis of acinar cells seemed to stimulate the proliferation of duct cells, which comprised the main cell components in the exocrine pancreas after the disappearance of acinar cells.

Immunocytochemical Localization of Endocrine, Paracrine and Neurocrine Cells in the Avian Pancreas

Abstract Jain, D. K. and Goel, R. 1994. Immunocytochemical localization of endocrine, paracrine and neurocrine cells in the avian pancreas. J. Appl. Anim. Res., 5: 95–100. The distribution of Immunoreactive (IR) endocrine (G-cell), paracrine (D-cell) and neurocrine (VIP-) cell types were investigated in the avian (Gallus gallus) pancreas. Sections were immunocytochemically stained by avidin-biotin- peroxidase complex (ABC) technique utilizingantisera to gastrin (SHGI: 2–17), Somatostatin (SOM: 15–28) and vasoactive- intestinal peptide (VIP: 14–28) with DABTH yielding reddish brown colour. G-cells were located both in acinar tissue and in the islets of dorsal, ventral and splenic pancreatic lobes. D-cells with blunt cytoplasmic processes (Paracrine) were found at the islet periphery. VIP-nerve fibers were found innervating both the exocrine and the endocrine portions and the blood vessels. This suggests the local release of neuronal VIP that stimulates pancreatic secretion. These investigations are helpful...

Peptide YY in the mammalian pancreas: immunocytochemical localization and immunochemical characterization

Peptide YY (PYY) was demonstrated by immunochemical and/or immunocytochemical methods in endocrine cells in the pancreas of adult mice, rats, guinea-pigs, cats, dogs, pigs and cows. In the pancreas of mouse and rat, immunoreactive PYY was observed in a major subpopulation of the glucagon cells (splenic lobe of the pancreas); immunoreactive PYY also occurred in a subpopulation of the pancreatic polypeptide (PP) cells (duodenal lobe), and in a few extra-insular endocrine cells dispersed throughout the pancreatic parenchyma. In the pancreas of cat, dog and pig immunoreactive PYY was found to coexist with PP, but not with glucagon. Radioimmunoassay (RIA) revealed PYY-like material in extracts of pancreas (and colon) of all the species examined. The highest concentrations were found in the pancreas of cat and mouse; moderate amounts were found in the rat and only small amounts were detected in guinea-pig and pig. The concentrations in the pancreas were uniformly much lower than those in the colon. Analysis by high performance liquid chromatography (HPLC) showed that the PYY-immunoreactive material from pancreas (and rat colon) had an elution profile very similar to that of synthetic PYY, and distinct from that of PP and neuropeptide Y.

Pancreatic Splenic Lobe Organ Culture System: Viability and Amylase Release

An organ explant culture system for the intact chick pancreatic splenic lobe (SL) was characterized for exocrine function. Organ cultures were prepared using the pancreatic splenic lobe from 9- and 15-day-old male broiler chicks (Arbor Acres × Arbor Acres) to characterize amylase release as well as tissue integrity during 2, 4, 8, and 12 h of incubation. Light microscopy studies indicated necrosis of the exocrine pancreatic acini after 4 h of incubation. Changes in islets of Langerhans were noted 4 h after incubation, but islet structural integrity remained intact for up to 12 h of incubation. Lactate dehydrogenase (LD) levels measured in the culture medium did not increase significantly from 2 to 4 h of incubation. After 4 h of incubation, total LD levels increased (P < .05) for the 9-day-old SL cultures, and LD levels increased (P < .01) per unit weight of SL for the 15-day-old cultures. Medium amylase activity did not increase after 2 h of incubation. Large increases occurred for total amylase activity and amylase activity per unit weight of SL between 4 and 12 h of incubation for both 9- and 15-day-old cultures. Histological examination as well as increases in LD and amylase activities for total and per unit weight of SL in the incubation medium suggest that the viability of the 9- and 15-day-old SL organ incubation system decreases after 4 h.