• Animal cells and systems
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• v.4 no.2
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• pp.187-193
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• 2000

Regional distribution and relative frequency of endocrine cells in the pancreas of the red-eared slider, Trachemys scripta elegans, were investigated by immunohistochemical methods. Chromogranin (Cg) A-, serotonin-, insulin-, glucagon-, somatostatin-, bovine pancreatic polypeptide (BPP)- and human pancreatic polypeptede (HPP)-immunoreactive cells were identified in this study. Most of immunoreactive cells in the exocrine and endocrine pancreas (Langerhans islet) were generally spherical or spindle-shaped (open-typed cell), while occasionally cells round in shape (close-typed cell) were found in the basal portion or interepithelial regions of the pancreatic duct. These immunoreactive cells were located in the exocrine, endocrine pancreas and/or basal or interepithelial portion of the pancreatic duct. Serotonin-immunoreactive cells were found in the basal portion of epithelia of the pancreatic duct at a low frequency and interacinar region of the exocrine at a moderate frequency. Insulin-immunoreactive cells were found in the central portion of the endocrine pancreas, interacinar regions of the exocrine pancreas and basal portion of the epithelia of the pancreatic duct at high, moderate and low frequencies, respectively. Glucagon-immunoreactive cells were detected in the periphery of the endocrine pancreas, interacinar region of the exocrine pancreas and basal portion of the epithelia or interepithelia of the pancreatic duct at high, moderate and moderate frequencies, respectively. Somatostatin-immunoreactive cells were dispersed in the whole area of the endocrine pancreas, interacinar regions of exocrine pancreas and basal portion of the epithelia or interepithelia of the pancreatic duct at a moderate frequency. BPP- and HPP-immunoreactive cells were detected in the iinteracinar region of the exocrine pancreas at moderate and hige frequencies, respectively. However, no Cg A- and motilin-immunoreactive cells were detected in this study.

• The Korean Journal of Pharmacology
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• v.30 no.2
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• pp.205-215
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• 1994

It is well known that chronic stimulation with CCK gives rise to growth of exocrine pancreas and to increased content of enzyme proteins in pancreas. However, littls Is known about changes of the secretory function of exocrine pancreas which has been chronically stimulated with CCK, especially about the responsiveness to secretagogues such as CCK, caerulein and carbachol. The present study was performed to investigate the effect of camostat on secretory profiles and the responsiveness to secretagogues of exocrine pancreas by observing in vitro amylase release stimulated by cholecystokinin-octapeptide(CCK-8) and carbachol in dispersed isolated pancreatic acini from camostat-treated rats for 4 or 10 days. The results summarized as follows : 1) The maximal effective concentration of CCK-8 in amylase release in the camostat treated group was greater than control group, but that of carbachol was not different between groups. 2) Analysis of the stimulated amylase release as the percentage of the maximal response revealed that camostat treatment caused right-shift of the dose-response curve of CCK-8. Camostat did not cause significant changes in the dose-response curve of carbachol. 3) There were considerable increases in the amylase release in the camostat-treated group, compared to the control when acini were stimulated with CCK-8 $10^{-9}\;M$ and carbaochol $10^{-6}\;M$, and higher concentrations. 4) There was a reverse correlation between the tissue content and the maximal release(percent of the total content) of amylase. These results suggest that chronic exposure of exocrine pancreas to increased endogenous CCK can enhance the responsiveness of exocrine enzyme secretion to secretagogues, especially at higher concentrations of CCK and carbachol.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.2
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• pp.185-192
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• 1998

A role of endogenous somatostatin in pancreatic exocrine secretion induced by intrapancreatic cholinergic activation was studied in the isolated rat pancreas perfused with modified Krebs-Henseleit solution. Intrapancreatic neurons were activated by electrical field stimulation (EFS: 15 V, 2 msec and 8 Hz). Pancreatic exocrine secretion, including volume flow and amylase output, and release of somatostatin from the pancreas were respectively determined. Somatostatin cells in the islet were stained with an immunoperoxidase method. EFS significantly increased pancreatic volume flow and amylase output, which were reduced by atropine by 59% and 78%, respectively. Intraarterial infusion of either pertussis toxin or a somatostatin antagonist resulted in a further increase in the EFS-evoked pancreatic secretion. EFS also further elevated exocrine secretion in the pancreas treated with cysteamine, which was completely restored by intraarterial infusion of somatostatin. EFS significantly increased not only the number of immunoreactive somatostatin cells in the islet but also the concentration of immunoreactive somatostatin in portal effluent. It is concluded from the above results that intrapancreatic cholinergic activation elevates pancreatic exocrine secretion as well as release of endogenous somatostatin. Endogenous somatostatin exerts an inhibitory influence on exocrine secretion induced by intrapancreatic cholinergic activation via the islet-acinar portal system in the isolated pancreas of the rat.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.3
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• pp.169-174
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• 2003

${\gamma}$-Aminobutyric acid (GABA) has been reported to enhance exocrine secretion evoked not only by secretagogues but also by intrinsic neuronal excitation in the pancreas. The pancreas contains cholinergic neurons abundantly that exert a stimulatory role in exocrine secretion. This study was undertaken to examine effects of GABA on an action of cholinergic neurons in exocrine secretion of the pancreas. Intrinsic neurons were excited by electrical field stimulation (EFS; 15 V, 2 msec, 8 Hz, 45 min) in the isolated, perfused rat pancreas. Tetrodotoxin or atropine was used to block neuronal or cholinergic action. Acetylcholine was infused to mimic cholinergic excitation. GABA $(30{\mu}M)$ and muscimol $(10{\mu}M)$, given intra-arterially, did not change spontaneous secretion but enhanced cholecystokinin (CCK; 10 pM)-induced secretions of fluid and amylase. GABA (3, 10, $30{\mu}M$) further elevated EFS-evoked secretions of fluid and amylase dose-dependently. GABA (10, 30, $100{\mu}M$) also further increased acetylcholine $(5{\mu}M)$-induced secretions of fluid and amylase in a dose-dependent manner. Bicuculline $(10{\mu}M)$ effectively blocked the enhancing effects of GABA $(30{\mu}M)$ on the pancreatic secretions evoked by either EFS or CCK. Both atropine $(2{\mu}M)$ and tetrodotoxin $(1{\mu}M)$ markedly reduced the GABA $(10{\mu}M)$-enhanced EFS- or CCK-induced pancreatic secretions. The results indicate that GABA enhances intrinsic cholinergic neuronal action on exocrine secretion via the $GABA_A$ receptors in the rat pancreas.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.4
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• pp.427-432
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• 1999

Although importance of intrapancreatic neurons containing gastrin-releasing peptide (GRP) in control of exocrine secretion has been raised, the nature of GRP in the pancreas is unclear. Thus, the present study was undertaken to see distribution, content and molecular heterogeneity of immunoreactive GRP in the rat pancreas. Content of immunoreactive GRP in the rat pancreas was $2.99\;{\pm}\;0.66$ ng/g wet tissues determined by radioimmunoassay. Immunoreactive GRP was most abundantly expressed in the duodenal part among 3 parts of the pancreas; duodenal, body and splenic part. Vagotomy failed to change the content of immunoreactive GRP in the pancreas. Three distinct forms of immunoreactive GRP, very identical to GRP-27, bombesin-24 and neuromedin C, were observed in the rat pancreas by using reversed phase $C_{18}$ HPLC and Sephadex G-50 superfine column chromatography. Cell bodies of neurons containing immunoreactive GRP were scattered in pancreatic connective tissues and their nerve fibers innervated pancreatic acini and large ducts as determined by immunohistochemistry. The present results suggest that three distinct forms of GRP exist in intrapancreatic GRPergic neurons, which exert a stimulatory role in pancreatic exocrine secretion in rats.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.177-178
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• 1989

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.219-229
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• 1996

In order to investigate intra-pancreatic cholinergic roles on insulin action in exocrine secretion, the pancreas was isolated from rats and continuously perfused with modified Krebs-Henseleit solution. Intra-arterial infusion of insulin (100 nM) or cholecystokinin (CCK, 14 pM) alone resulted in stimulation of the volume flow and amylase output. Also insulin potentiated the action of CCK in the exocrine secretion. Tetrodotoxin and atropine completely abolished the potentiating action of insulin and CCK as well as the action of insulin alone, but did not change the action of CCK alone. In order to see an effect of intra-pancreatic neural activation on the insulin action, electrical field stimulation (EFS) with parameters of 20 V, 2 msec and 8 Hz was applied to the isolated pancreas for 10 min under 2.5 or 18 mM glucose background. The EFS voltage-dependently elevated the flow rate and amylase output, and potentiated exocrine secretion in 18 mM glucose infusion compared with 2.5 mM glucose. The potentiating effects of EFS and 18 mM glucose were not observed in the streptozotocin-treated pancreas although it was perfused with 18 mM glucose. However, it was restored when the diabetic pancreas was perfused with porcine insulin(100 nM). Tetrodotoxin and atropine inhibited the pancreatic secretion induced by EFS with the background of 18 mM glucose. The results of present investigation indicate that the intra-pancreatic cholinergic tone exerts a stimulatory influence on the action of insulin in pancreatic exocrine secretion of rats.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.179-180
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• 1989

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.448-454
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• 1999

The regional distribution and relative frequency of the endocrine cells in the pancreas of the bean goose were investigated by immunohistochemical methods using 6 types of the specific antisera. Spindle shaped serotonin-immunoreactive cells were detected in the exocrine portions. Spherical or spindle shaped glucagon-immunoreactive cells were observed in the exocrine and dark and mammalian type islets. In the dark type islets, numerous cells were dispersed throughout whole islets but they were located in the peripheral regions of the mammalian type islets. No glucagon-immunoreactive cells were detected in light type islets. Round or spherical shaped insulin-immunoreactive cells were observed in the exocrine and dark, light and mammalian type islets. They were observed in the exocrine regions with a few numbers. Extremely rare cells were detected in central portion of the dark type islets but moderate to numerous cells were found in the central regions of the mammalian and light type islets, respectively. Spherical or spindle shaped somatostatin-immunoreactive cells were observed in the exocrine and dark, light and mammalian type islets. A few single cells were detected in the exocrine portions. In the dark type islets, numerous cells were dispersed throughout whole islets but a few to moderate numbers of cells were located in the peripheral regions of the light and mammalian type islets. Moderate numbers of the bovine pancreatic polypeptide-immunoreactive cells were found in the exocrine portions with round, spherical or spindle shape. But no bovine Sp-1/chromogranin-immunoreactive cells were observed in this study.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.217-221
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• 2003

To clarify the roles of gonadal steroids on pancreatic exocrine secretion, effects of progesterone and estradiol-$17{\beta}$ on spontaneous and secretagogue-induced exocrine response of isolated perfused rat pancreas were investigated. Intra-arterial infusion of progesterone resulted in significant increase of the spontaneous pancreatic fluid and amylase secretion dose-dependently. However, estradiol-$17{\beta}$ did not exert any influence on spontaneous pancreatic exocrine secretion. Exogenous secretin, cholecystokinin (CCK), and acetylcholine markedly stimulated pancreatic fluid and amylase secretion. Progesterone initially enhanced secretin-induced amylase secretion, but this stimulatory response declined thereafter to basal value. Moreover, secretin-induced fluid secretion was not affected by infusion of progesterone. Therefore, initial increase of secretion-induced amylase secretion by progesterone seems to be a non-specific action by washout effect of secretin. Estradiol-$17{\beta}$ failed to change the secretin-induced fluid and amylase secretion. Both progesterone and estradiol-$17{\beta}$ did not exert any influence on CCK-induced fluid and amylase secretion. Acetylcholine-induced exocrine secretion of isolated perfused pancreas also was not affected by intra-arterial infusion of progesterone or estradiol-$17{\beta}$. It is concluded from the above results that progesterone could enhance the spontaneous pancreatic fluid and amylase secretion of isolated perfused rat pancreas through non-genomic shortterm action, and that these effects could be masked by more potent stimulants such as secretin, CCK, and acetylcholine.