• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.745-754
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• 1997

This study was designed to investigate the effects of cholate and deoxycholate on pancreatic exocrine secretion in conscious sheep with external bile and pancreatic fistulae. Bile and pancreatic juices were collected for a basal period of 2 hours. The pancreatic juice was returned to the intestine. Bile salts were infused into the jugular vein or duodenum for 90 minutes at the rate of 0.7mg/kg/min. Cholate and deoxycholate significantly increased the flow rate, pH and bicarbonate concentration of bile juice, but decreased the flow rate of pancreatic juice. The effects induced by intraduodenal infusion of both bile salts were significantly greater than those by intravenous infusion. Protein concentration and amylase activity in pancreatic juice were also significantly decreased by both bile salts; the effects were greater when the bile salts were infused into the duodenum than into the vein. The inhibitory effects induced by deoxycholate infusion were significantly greater than those by cholate infusion. The plasma concentration of secretin was significantly increased by intravenous infusion of deoxycholate, but it was not effected by intraduodenal infusion of both bile salts. The results indicated that cholate and deoxycholate markedly increased the secretion of bile juice and decreased the pancreatic exocrine secretion, although these effects were variable depending on the chemical composition or infusion routes.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.83-90
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• 1997

Aim of this study was to investigate if pancreatic polypeptide (PP) reduced the insulin action via the intra-pancreatic cholinergic nerves in the isolated rat pancreas. The pancreas was isolated from rats and perfused with intra-arterial infusion of modified Krebs-Henseleit solution containing 2.5 mM glucose at a flow rate of 1.2 ml/min. Simultaneous intra-arterial infusion of insulin (100 nM) resulted inpotentiation of the pancreatic flow rate and amylase output which were stimulated by cholecystokinin (CCK, 14 pM). These potentiating actions of insulin on the CCK -stimulated pancreatic exocrine secretion were completely abolished by administration of rat PP. Vesamicol, a potent inhibitor of vesicular acetylcholine storage, and tetrodotoxin (TTX) also significantly reduced the combined actions of insulin and CCK. Administration of carbamylcholine, an acetylcholine agonist, completely restored the vesamicol- or TTX-induced inhibition of the potentiation between insulin and CCK. Also rat PP failed to attenuate the restoring effect of carbamylcholine. Electrical field stimulation (15-30 V, 2 msec and 8 Hz) resulted in a significant increase in the pancreatic flow rate and amylase output in voltage-dependent manner. Effects of electrical field stimulation were augmented by endogenous insulin. Rat PP also suppressed the pancreatic exocrine secretion stimulated by electrical field stimulation. These observations strongly suggest that PP inhibits the potentiating actions of insulin on CCK -stimulated pancreatic exocrine secretion by suppression of the intra-pancreatic cholinergic activity in the isolated rat pancreas.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.249-256
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• 1986

The present study was performed to investigate a possible influence of the adrenergic nervous system on pancreatic exocrine secretion stimulated by intraduodenal acid perfusion. Pancreatic secretion was collected in rats anesthetized with urethane after 24 hours fasting. The duodenal lumen was perfused (0.2 ml/min) with HCI solution in a concentration of 0.005, 0.01, 0.02, 0.05 or 0.1 N When the volume of panceratic juice secreted for IS min became constant phentolamine (1 mg/kg), $noradrenaline\;(10\;{\mu}g/kg),\;Propranolol\;(1\;mg/kg),\;and \;isoproterenol\;(1\;{\mu}g/kg)$ were administered through the jugular vein in bolus. The secretory volume and protein output were measured in the pancreatic juice collected for 15 min. 1) HCI, perfused intraduodenally in graded concentrations from 0.005 N to 0.1 N, increased the pancreatic secretory volume and protein output dose-dependently. 2) In the basal state as well as in the stimulated state by the duodenal acid perfusion, phentolamine increased the pancreatic secretory volume and protein output while propranolol inhibited the volume and protein output. 3) In the basal state, noradrenaline did not change the pancreatic secretory volume but increased the protein output while isoproterenol increased both of the secretory volume and the protein output. These results strongly suggest that ${\alpha}-adrenoceptors$ in the rat pancreas exert an inhibitory influence on the pancreatic exocrine secretion including volume and protein output in the basal state as well as in the stimulated state by the intraduodenal acid perfusion while ${\beta}-adrenoceptors$ play a stimulatory role in the pancreatic exocrine secretion. However, in the physiological situation, adrenergic excitation may stimulate the protein output through ${\beta}-adrenoceptors$ without change in the secretory volume in the rat pancreas.

• The Korean Journal of Pharmacology
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• v.13 no.2
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• pp.41-48
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• 1977

In 1968, Case et al. first studied the importance of cyclic AMP as an intermediate in the action of secretin and cholecystokinin-pancreozymin and they suggested that the action of secretin, not that of cholecystokinin-pancreozymin, may be mediated through cyclic AMP. Recently Albano et al. reported that in the exocrine pancreas each of the two major physiological functions is modulated a specific cyclic nucleotide, enzyme secretion by cyclic GMP, and fluid and ionic secretion by cyclic AMP. But in pancreas still conflicting results have been reported on the role of cyclic nucleotides in enzyme and electrolyte secretion. In these study, the role of cyclic nucleotides in the exocrine pancreatic secretion was examined. The results are as follows. 1) Very strong stimulation on amylase release from guinea pig pancreatic slice was produced by 1 unit of cholecystokinin-pancreozymin but as compared to that of cholecystokinin-pancreozymin very weak response was observed by 1 unit of secretion or $1\;{\mu}g$ of VIP. 2) Both cholecystokinin-pancreozymin and acetylcholine produced a rapid and marked rise in cyclic GMP as well as cyclic AMP in isolated pancreatic tissue. However, both secretin and VIP failed to alter significantly the basal level of cyclic GMP in pancreatic fragments. 3) Atropine inhibited acetylcholine mediated amylase release, but did not affect the cholecystokinin-pancreozymin response. Furthermore, atropine pretreatment produced a marked inhibitory effect on the increase of tissue cyclic nucleotides induced by cholecystokinin-pancreozymin and acetylcholine. In summary, these results suggest that whereas the pancreatic secretion produced by secretin and VIP is modulated by the formation of cyclic AMP, the pancreatic enzyme secretion in response to cholecystokinin-pancreozymin and acetylcholine is triggered by both cyclic AMP and cyclic GMP.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.657-663
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• 1998

The enzyme responsible for the synthesis of nitric oxide (NO) from L-arginine in mammalian tissues is known as nitric oxide synthase (NOS) (EC.1.14.13.39). In the present study, the role of NO in the regulation of exocrine secretion was investigated in rat pancreatic acinar cells. Treatment of rat pancreatic acinar cells with cholecystokinin-octapeptide (CCK-OP) resulted in an increase in the arginine conversion to citrulline, the amount of $NO_X$, the release of amylase, and the level of CGMP. Especially, CCK-OP-stimulated increase of arginine to citrulline transformation, the amount of $NO_X$, and CGMP level were completely counteracted by the inhibitor of NOS, NG-monomethyl-L-arginine (MMA), by contrast, that of amylase release was partially reduced. Furthermore, MMA-induced decrease of NOS activity and amylase release showed dose-dependent pattern. The data on the time course of CCK-OP-induced citrulline formation and CGMP rise indicate that NOS and guanylate cyclase were activated by treatment of CCK-OP. However, the mechanism of agonist-stimulated guanylate cyclase activation in acinar cells remains unknown. Therefore, activation of NOS is one of the early events in receptor-mediated cascade of reactions in pancreatic acinar cells and NO, not completely, but partially mediate pancreatic enzyme exocrine secretion.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.307-312
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• 2011

It has been rereported that axons which display 5-hydroxytryptamine (5-HT) immunoreactivity are abundant in the pancreas and the majority of serotonergic axons terminate within intrapancreatic ganglia, islet and acini. This histological result strongly suggests that intrapancreatic serotonergic nerves could affect to the pancreatic endocrine and exocrine secretion. Thus, this study was aimed to investigate whether intrapancreatic serotonergic nerves could affect pancreatic exocrine secretion and an action mechanism of the intrapancreatic serotonergic nerves. The rats were anesthetized with a single injection of urethane. The median line and the abdominal aorta was carefully dissected and cannulated with PE-50 tubing just above the celiac artery, and then tightly ligated just below the superior mesenteric artery. The pancreatic duct was also cannulated with Tygon microbore tubing. With the addition of serotonin, pancreatic volume flow and amylase output were significantly inhibited electrical field stimulation (EFS). On the other hand, pancreatic volume flow and amylase output were significantly elevated in EFS with the addition of spiperone. EFS application, however, pancreatic volume flow and amylase output had no significant change in cholecystokinin (CCK) alone when serotonin was applied under a 5.6 mM glucose background. Pancreatic volume flow and amylase output under 18 mM glucose background were significantly elevated in CCK plus serotonin than in CCK alone. These data suggest that intrapancreatic serotonergic nerves play an inhibitory role in pancreatic exocrine secretion and an important role in the insulin action or release.

• 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 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.

• Archives of Pharmacal Research
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• v.18 no.6
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• pp.434-439
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• 1995

In pancreatic cells, NO formation is associated with increased levels of cGMP and endocrine/exocrine secretion. In the present study, the role of NO in the regulation of exocrine secretion was investigated in rat pancreatic tissues. Treatment of rat pancreatic tissue with sholecystokinin-pancreozymin (CCK-PZ) resulted in an significant increase in arginine conversion to citruline, the amount of nitrite/nitrate, the release of amylase, and the level of cGMP. Furthermore, CCK-PZ stimulated increase of amylase release and conversion of arginine to citrulline transformation were counteracted by the inhibitor of NO synthase, $N^G-nitro-L-arginine$ methyl ester. The results on the time course of CCK-PZ-induced citrulline formation within the first seconds of simulation. The kinetics of citrulline accumulation correlate well with those of cGMP rise, which further confirms the conclusion that NO mediates the response to CCK-PZ by cGMP.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.8
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• pp.1044-1049
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• 2000

Three wethers fitted with silastic catheters for collection of pancreatic juice, and cannulas located in the abomasum and the duodenum were used to investigate the effects of different hay and energy intake on pancreatic exocrine secretion. The wethers were fed Italian ryegrass hay or alfalfa hay at maintenance energy requirement and alfalfa hay ad libitum. High energy intake from alfalfa significantly increased abomasal flow of dry matter and both the concentration and daily secretion of ${\alpha}-amylase $. The high energy intake also tended to increase daily secretion of lipase, trypsin and chymotrypsin through the large volume of pancreatic juice. Compared with Italian ryegrass hay, alfalfa hay at the maintenance decreased abomasal dry matter flow, but increased concentration of ${\alpha}-amylase $ in the pancreatic juice, and tended to increase daily secretion of ${\alpha}-amylase $. The secretion of the other enzymes was not different between the two hays at maintenance intake. These results suggest that the kind of hay could change the concentration of ${\alpha}-amylase $ in the pancreatic juice, and that the intake level of alfalfa hay affects the ${\alpha}-amylase $ concentration and the juice volume secreted from the pancreas.