Exocrine Function In Rats Research Articles

The evaluation of 2.3-diazepine influence on tissue respiration of the liver and its exocrine function in rats with a rotenone model of Parkinson’s disease

The evaluation of 2.3-diazepine influence on tissue respiration of the liver and its exocrine function in rats with a rotenone model of Parkinson’s disease

Exocrine pancreatic function in rats after acute pancreatitis.

The present studies were performed to evaluate pancreatic exocrine function in rats during the early stage of acute pancreatitis in two models: one is edematous pancreatitis induced by four subcutaneous injections of 20 micrograms/kg body weight of cerulein at hourly intervals and the other is hemorrhagic pancreatitis induced by retrograde infusion of 0.4 ml/kg body weight of 3% sodium taurocholate (NaTc) into the pancreatic duct. Secretory studies were performed in vivo under urethane anesthesia at various times after induction of acute pancreatitis. Basal pancreatic fluid secretion was significantly elevated after induction of acute pancreatitis in both the cerulein and the NaTc models, reaching the peak level on postpancreatitic days 1 and 3, respectively. In both models of rats, a stepwise increasing dose of cerulein was unable to cause a further increase in fluid secretion above the basal level, whereas it caused a dose-dependent increase in protein output in both models, although the responsiveness and the sensitivity were markedly reduced compared with the controls. In contrast to cerulein, secretin caused a dose-dependent increase in fluid secretion in both models of pancreatitis. In cerulein-induced postpancreatitic rats, secretin also caused a dose-dependent increase in protein output and bicarbonate concentration, but it had only a small effect at certain doses in NaTc-induced postpancreatitic rats. These results indicate that basal pancreatic fluid secretion was greatly increased but the secretory response to cerulein stimulation was reduced in acute pancreatitis early after the onset but was not reduced to secretin stimulation and that protein output and bicarbonate concentration were reduced depending on the severity of pancreatitis (NaTc-pancreatitis > cerulein-pancreatitis.

Neurohormonal regulation of pancreatic exocrine function in rats without gene expression of the cholecystokinin-A receptor.

Otsuka Long-Evans Tokushima Fatty (OLETF) rats revealed no or reduced expression of the cholecystokinin (CCK)-A receptor gene in the pancreas and that the pancreas of this strain of rats did not respond to CCK stimulation. We examined whether the pancreatic responses to hormonal and neural stimulation except for CCK in OLETF rats were maintained. The pancreatic responses of conscious OLETF rats to various stimuli were examined in vivo and compared with those of control (Long-Evans Tokushima; LETO) rats. Moreover, the levels of expression of CCK-A and -B receptor genes in the small intestine were examined. Pancreatic responses to intravenous injection of secretin and acetylcholine and to intracerebroventricular administration of thyrotropin-releasing hormone were comparable in OLETF and LETO rats. However, responses to intravenous injection of neuromedin C, to intraduodenal injection of capsaicin, and to intragastric injection of a liquid meal were impaired in OLETF rats. CCK-A receptor mRNA was not expressed in the small intestine of OLETF rats but was in LETO rats. The pancreatic responses to various stimuli in OLETF rats were well conserved except for the involvement of CCK-A receptor function. OLETF rats are confirmed as a new experimental model deficient in CCK-A receptor gene expression and represent a useful tool for studying the physiological role of these in vivo.

Effect of the cholecystokinin receptor antagonist loxiglumide on pancreatic exocrine function in rats after acute pancreatitis.

Recent studies have demonstrated that cholecystokinin (CCK) receptor antagonists not only reduce the severity of pancreatitis but also inhibit pancreatic regeneration after pancreatitis. This study was undertaken, therefore, to examine the effects of the CCK receptor antagonist loxiglumide on the exocrine pancreas when given after an episode of acute pancreatitis that was induced in rats by a 4-h subcutaneous infusion of 20 micrograms/kg body weight/h cerulein. Biochemical changes and secretory function in response to 100 ng/kg body weight cerulein were determined after a 6-day treatment with saline, loxiglumide (50 mg/kg body weight), or CCK-8 (2.5 micrograms/kg body weight), which was given three times a day starting 24 h after the induction of acute pancreatitis. In the saline-treated rats, pancreatic enzyme contents and pancreatic juice and protein output were significantly low, whereas the pancreatic weight and protein and DNA contents were comparable to those of the controls without pancreatitis. Loxiglumide treatment, although significantly decreasing protein output, had no influence on pancreatic weight, protein and DNA contents, or pancreatic juice flow but increased the amylase and lipase contents compared to those of the saline-treated postpancreatitic rats. CCK-8 treatment also had no influence on pancreatic weight or protein and DNA contents but significantly increased the pancreatic enzyme contents and pancreatic juice and protein output compared to those of the saline-treated postpancreatitic rats. These results suggest that loxiglumide does not significantly inhibit the recovery of exocrine function but appears to accelerate the increase in pancreatic amylase and lipase contents even when given after an attack of acute pancreatitis.

The effects of FK506 and cyclosporine on the exocrine function of the rat pancreas.

The effects of FK506 on exocrine function of the pancreas in Sprague-Dawley rats were examined and compared with those of cyclosporine. FK506 did not affect the levels of amylase and lipase in the pancreas of rats given the drug orally in a daily dose of 1 or 5 mg/kg for 2 weeks. Furthermore, the pancreas of the rats showed good exocrine secretion of enzymes such as amylase and lipase on stimulation with carbachol in vitro. Cyclosporine 50 mg/kg given in the same way as FK506 also was free of effect on enzyme levels in the rat pancreas, but the exocrine secretion of the enzyme from the pancreatic lobules on stimulation with carbachol was impaired. It is concluded that FK506 does not affect pancreatic exocrine function in rats.

P-317 - Pancreatic endocrine and exocrine function in rats with streptozotocin diabetes.

P-317 - Pancreatic endocrine and exocrine function in rats with streptozotocin diabetes.

ラットにおけるｃａｅｒｕｌｅｉｎ刺激下すい外分泌におよぼす肝切除の影響

ラットにおけるｃａｅｒｕｌｅｉｎ刺激下すい外分泌におよぼす肝切除の影響

Effect of synthetic protease inhibitor camostate on pancreatic exocrine function in rats.

Pancreatic exocrine function in rats given synthetic protease inhibitor camostate (200 mg/kg body weight) perorally once daily for 10 days was investigated. Pancreatic wet weight was significantly increased in the camostate-treated rats. The increase in pancreatic weight was associated with pronounced hypertrophy and moderate hyperplasia. Total amylase, trypsin, and lipase contents in the pancreas were also increased in the camostate-treated group compared with the control rats. Secretory patterns of pancreatic juice and amylase in response to caerulein were similar in both groups, whereas the dose-response curve for pancreatic juice secretion in the camostate-treated rats was shifted tenfold toward higher concentrations of caerulein. Basal and caerulein-stimulated flow rates of pancreatic juice were significantly greater in the camostate-treated rats than the control rats, although both groups showed a threefold increase over basal secretion in response to maximal stimulation. Amylase outputs in basal state and in response to submaximal doses of caerulein were significantly lower, whereas those to maximal and supramaximal doses were significantly greater in the camostate-treated animals than that in the control rats. These results indicate that treatment with camostate induces pancreatic hypertrophy and hyperplasia, and that the secretory function of the hypertrophied pancreas is quantitatively but not qualitatively altered.

Effect of aging on pancreatic secretion in rats

We have characterized the effects of aging on the pancreatic exocrine secretory response to the normal stimulatory hormones, secretin, and cholecystokinin. Young (6 month old) and aged (26 months old) male Sprague-Dawley rats were prepared with pancreatic fistulas and challenged with different doses of secretin (0.03, 0.06, and 0.12 nmol/kg) and cholecystokinin-8 (0.3, 0.6, and 1.2 nmol/kg) intravenously. The pancreatic secretion was measured for volume and bicarbonate and protein outputs. Our results show that in aged rats, the basal pancreatic secretion volume and protein and bicarbonate outputs were significantly reduced, and the pancreatic secretion volume and protein and bicarbonate responses to graded doses of secretin or cholecystokinin-8 were significantly reduced. This study demonstrates that pancreatic exocrine function in rats diminishes with age.

Effects of long-term dietary modifications on pancreatic enzyme activity.

The effect of long-term dietary modification on pancreatic exocrine function in rats has been investigated by examining responses to cholecystokinin-pancreozymin stimulation, using a method of direct pancreatic duct cannulation. Residual pancreatic enzyme activity remaining in the whole pancreas following stimulation was also measured. After 6 months of dietary modification, changes in the pancreatic secretions of high-protein- or high-fat-fed animals were similar to those reported in short-term studies in which elevation of trypsin and lipase activity occurred in the pancreas. However, between 6 and 9 months, both volume and amylase activity of pancreatic secretions decreased in animals fed a high-protein diet. At 6 and 9 months, animals fed a high-carbohydrate diet had increased amounts of amylase and decreased trypsin in both pancreatic secretion and homogenate, similar to short-term changes previously reported. High-carbohydrate-fed animals had decreased lipase activity in pancreatic secretions, but lipase activity in pancreatic homogenates was increased, similar to levels found in animals fed a high-fat diet.

Effects of Long‐Term Dietary Modifications on Pancreatic Enzyme Activity

Summary:The effect of long‐term dietary modification on pancreatic exocrine function in rats has been investigated by examining responses to cholecystokinin‐pan‐creozymin stimulation, using a method of direct pan‐creatic duct cannulation. Residual pancreatic enzyme activity remaining in the whole pancreas following stimulation was also measured. After 6 months of dietary modification, changes in the pancreatic secretions of high‐protein‐or high‐fat‐fed animals were similar to those reported in short‐term studies in which elevation of trypsin and lipase activity occurred in the pancreas. However, between 6 and 9 months, both volume and amylase activity of pancreatic secretions decreased in animals fed a high‐protein diet. At 6 and 9 months, animals fed a high‐carbohydrate diet had increased amounts of amylase and decreased trypsin in both pancreatic secretion and homogenate, similar to short‐term changes previously reported. High‐carbohydrate‐fed animals had decreased lipase activity in pancreatic secretions, but lipase activity in pancreatic homogenates was increased, similar to levels found in animals fed a high‐fat diet.