• 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.1 s.21
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• pp.29-33
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• 1977

Effects of 50% glucose solution on pancreatic exocrine function were studied in rat, rabbit and cat. The alterations during the resting state, the continuous intravenous infusion of secretin and the infusion of secretin with CCK-PZ were determined. 1) No change of pancreatic secretion in rat was observed by intragastric administration of the hypertonic glucose solution. 2) Intragastric administration of the hypertonic glucose solution in rabbit produced the inhibitory effect on pancreatic secretion during secretion infusion. 3) While secretin with CCK-PZ were infused continuously, intragastric administration of the hypertonic glucose solution revealed the marked inhibitory effect on pancrcreatic secretion in cat. Oral administration of the hypertonic glucose solution produced no significant inhibition in the resting gland but markedly depressed the pancreatic flow and enzyme concentration in the secretin or CCK-PZ stimulated gland. It is felt that the inhibitory response of exocrine pancreas induced by intragastric hytertonic glucose solution is resulted in interaction between secretory hormone and gastric mucosal factor possibly enteroglucagon.

• 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.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.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.711-719
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• 2000

The characteristics of the exocrine pancreatic secretions in pigs and its hormonal regulation as influenced by dietary lipids are reviewed. There is clear evidence that the secretion of lipolytic enzymes is positively correlated with the amount of fat consumed by the pig. For example, there was an increase in the specific lipase activity by 83% after the dietary fat content was increased from 5% to 25%. Moreover, it was shown that also the quality of fat has an influence on exocrine pancreatic secretions. Peroxidized canola oil stimulated total lipase secretion much more than non-peroxidized oil. The influence of fatty acid composition on exocrine pancreatic secretions is discussed equivocally. Some authors showed that saturated fats stimulated the exocrine pancreatic secretions more than unsaturated. Others showed that the chain length of fatty acids had a strong influence on pancreatic secretions as well. Due to the different surgical methods used for sampling of pancreatic juice and wide variety of fats and oils used in these studies, direct comparisons between studies are extremely difficult to make. Plasma levels of hormones such as cholecystokinin (CCK), neurotensin (NT) and peptide YY (PYY) are influenced by the nutrient composition of the diet. With increasing amounts of fat present in the small intestine, the release of these hormones was stimulated. There is evidence that CCK release is dependent on the chain length of the fatty acids. Medium chain triglycerides stimulated the CCK release more than long chain triglycerides. Neurotensin was released more by unsaturated than by saturated fatty acids; similar results were observed for the PYY release. However, results are contradictory and further investigations are warranted that focus on the underlying mechanisms involved in the regulatory response of the exocrine pancreas to lipids of different origin.

• The Korean Journal of Physiology
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• v.25 no.1
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• pp.27-35
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• 1991

Generally, it has been known that cholecystokinin (CCK) release into the plasma is under cholinergic control, but secretin release is not. Thus in anesthetized dogs we studied the effect of atropine $(50\;{\mu}g/kg\;followed\;by\;50\;{\mu}g/kg/hr)$ on pancreatic secretion and plasma concentrations of bioactive CCK and immunoreactive secretin in response to intraduodenal perfusion of sodium oleate (1, 3 and 9 mmol/hr). The volume, protein output and bicarbonate output of the secretion were increased by sodium cleats and this oleate-induced secretion was decreased significantly by atropine administration. However the increased plasma CCK and secretin levels by sodium oleate were not changed by atropine. These results indicate that atropine suppressed sodium oleate-induced pancreatic secretion through inhibiting cholinergic mechanism directly rather than decreasing the release of pancreatic secretory hormones. In another set of experiments, bilateral cervical vagi were stimulated electrically to observe the changes of pancreatic secretion and the above two plasma hormone levels in the presence or absence of atropine. In the vagally stimulated dogs, the volume, protein output and bicarbonate output of the pancreatic secretion were increased significantly. Both plasma secretin and CCK were concomitantly released significantly by vagal stimulation. Atropine significantly depressed the pancreatic secretory response as well as the release of these two pancreatic secretory hormones. Therefore, we conclude that in the presence of atropine the depressed pancreatic response to vagal stimulation is at least, in part, due to decreased release of endogenous CCK and secretin. In the vagally stimulated animals, however, the involvement of direct cholinergic influence on pancreatic exocrine gland remains to be answered.

• 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.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.