Pancreatic response to bolus injection of cholecystokinin-pancreozymin in anaesthetized and conscious rats fed raw soyaflour

Pancreatic secretion was studied in rats fed raw soyafour before (basal) and after stimulation with cholecystokinin-pancreozymin (CCK) given in either ascending or descending dose orders ranging from 1.25 to 20 or from 20 to 1.25 Crick-Harper-Raper units (CHRU). These results were compared with those reported previously for animals fed a stock cube diet. Two experimental conditions were used: anaesthetized animals were tested immediately after cannulation of the pancreatic duct and conscious animals were tested 48 h after surgery. Basal flow was significantly increased in anaesthetized and conscious rats fed RSF compared with the respective animals fed cubes. Mean basal protein output was also increased, but this difference was not significant. The pancreatic response to the ascending and descending doses of CCK in anaesthetized rats fed RSF was linearly related to the log of the dose of CCK in both animals fed RSF and cubes, though the response to CCK was greater in the rats fed RSF. When ascending doses of CCK were given to conscious rats fed RSF, the protein output increased up to 10 CHRU of CCK but was inhibited by 20 CHRU of CCK, whereas it decreased after the first dose of CCK (1.25 CHRU) in animals fed cubes. When descending doses of CCK were given to animals fed RSF, protein output was greatest after the first dose and no simple relationship between dose and response was seen. Compared with rats fed cubes, the pancreas in rats fed RSF thus appears to respond to a given dose of CCK with increased secretion, and conscious animals fed RSF can tolerate a higher dose of CCK before protein output is inhibited. This is consistent with an increased population of acinar cells in the animals fed RSF, with each hypertrophied cell responding to CCK with increased secretion.     

Effect of exogenous and endogenous insulin on the secretory response of the pancreas to the octapeptide of cholecystokinin (CCK8) in normal rats

The author studied the effect of insulin on CCK8-stimulated secretion by the pancreas. CCK8 (0.6 nmol.kg-1) was administered to normal anaesthetized rats 30 min after the intravenous injection of insulin (10 U.kg-1), glucose (2 g.kg-1) or NaCl (controls). Pancreatic juice was collected from the intubated common bile duct. In rats given exogenous insulin, there were no statistically significant differences in total protein, amylase and trypsinogen output after CCK8 compared with the controls. In rats in which endogenous insulin secretion was stimulated with glucose, the amylase response to CCK8 was not significantly different from the control animals, but the trypsinogen response was significantly lower. The results show that insulin, in some still unknown manner, inhibits the trypsinogen secretory response to CCK8. In addition, they confirm data claiming that the synthesis and secretion of pancreatic amylase require a given critical ratio of insulin to glucose, or of insulin to the factor stimulating pancreatic secretion.     

Influence of glucocorticoids on the secretion of pancreatic juice in the rat

The influence of adrenalectomy and hydrocortisone treatment on the exocrine pancreatic secretion has been studied in anaesthetized rats. In the adrenalectomized animals Na+ administered in the saline solution provided for drinking was able to maintain standard sodium levels in serum. In these animals an increase of Na+ secretion in pancreatic juice was observed. Furthermore, the osmotic effect created by the increase in Na+ would account for the increase in pancreatic flow. In these adrenalectomized rats, an increase in K+ output is observed, which can be explained by the high K+ concentrations in serum. Likewise adrenalectomy decreased pancreatic enzyme secretion and produced a loss in weight of the organ that is accounted for by a lack of glucocorticoids. Hydrocortisone administration did not affect neither the secretion nor the weight of the pancreas of the control rats but the hormone proved to be effective in adrenalectomized rats producing a pancreatic secretion close to normal, balancing the secretory rate of water, Na+ and K+, completely restoring total protein secretion and the weight of the pancreas but amylase secretion in part only. It is therefore concluded that the weight of the pancreas and its exocrine secretion are clearly influenced by adrenalectomy and by substitution therapy with hydrocortisone. The administration of this hormone (25 mg.kg-1.day-1 along 6 days) did not affect intact animals.     

Nonparallel secretion of enzymes by the rabbit pancreas

Since nonparallel secretion of enzymes by the exocrine pancreas has been demonstrated with several experimental models, we were interested in verifying a recent claim that enzyme secretion remained strictly proportional (parallel) upon stimulation of the in vivo rabbit pancreas. Pancreatic juice was collected by extraduodenal cannulation of the pancreatic duct, in two different protocols. In the first protocol the administration of pentobarbital induces a mild anesthesia. Under this condition, amylase and chymotrypsin secretion remained parallel after cholecystokinin stimulation. In a second protocol, a deeper and constant anesthesia was attained with Fluothane resulting in a lower basal protein output than in the first protocol. Pancreatic secretion was collected under intravenous secretin perfusion (4.5 clinical units X kg-1 X h-1). After stabilization and basal collection periods, pancreatic secretion was stimulated with an i.v. bolus injection of either cholecystokinin (2 Ivy dog units/kg), caerulein (0.1 micrograms/kg), or carbachol (6 micrograms/kg). Upon stimulation of the pancreas, protein output increased an average of 30-fold and there was a concomitant 20-25% decrease in the ratio of the specific activities of amylase to chymotrypsin which resulted from a greater increase in the specific activity of chymotrypsin in pancreatic juice after stimulation of secretion. Thus, under appropriate conditions, nonparallel secretion of enzymes by the exocrine pancreas can be demonstrated in yet another experimental model. Furthermore, the proportion of amylase and chymotrypsin activities in pancreatic juice are once more shown to be dependent, up to a threshold, upon the rate of protein output by this exocrine gland.     

The effect of secretin and cholecystokinin-pancreozymin on the secretion of bile in the anaesthetized rabbit.

Effects of secretin and Cholecystokinin-Pancreozymin (CCK-PZ) on the secretion of bile in anaesthetized rabbits have been studied. Single injections of secretin (5.0 u.kg(-1) significantly increased the flow of bile irrespectively of whether the cystic duct was free or had been tied. A sustained increase in bile flow could be obtained by the continuous infusion of secretin. Cholecystokinin-Pancreozymin was effective in increasing the bile flow in doses of 1.0 u.kg(-1). Much of the effect could be attributed to contraction of the gallbladder but a significant increase in flow could still be elicited after ligation of the cystic duct. Our findings strongly suggest that the biliary secretion in rabbits is not as different from the general pattern as has previously been suggested.     

Diverse effects of phytohaemagglutinin on gastrointestinal secretions in rats.

Kidney bean lectin phytohaemagglutinin (PHA) is known for its binding capacity to the small intestinal surface inducing marked hyperplasia and hypertrophy and an increased pancreatic function. Recent observations indicate that PHA is able to attach to gastric mucosal and parietal cells. Therefore, we compared the effects of PHA on gastric acid secretion, and pancreatic amylase secretion in rats. To study gastric secretion in conscious animals, rats were surgically prepared with chronic stainless steel gastric cannula and with indwelling polyethylene jugular vein catheter. Acid secretion was determined by titration of the collected gastric juice to pH 7.0. Similar studies were performed to investigate the effect of PHA on pancreatic enzyme secretion in conscious rats supplied with pancreatic cannula. Pancreatic enzyme secretion was also studied in rats anesthetized with either halothane or urethane. In conscious rats PHA significantly inhibited basal acid secretion when compared to vehicle-treated controls. The effect was dose-dependent and reversible. On the other hand, given in the same doses as in the acid-secretory studies, PHA stimulated pancreatic amylase secretion in rats prepared with chronic pancreatic cannula. This effect was blocked by devazepide, a CCK-A receptor antagonist. In halothane-anesthetized rats PHA administration increased pancreatic amylase secretion, too. During urethane anesthesia, however, the stimulatory effect of PHA was not observed. These results provide evidence that intragastric PHA treatment induces opposite effects on gastric acid secretion and pancreatic enzyme secretion: it is a potent inhibitor of acid output, and a stimulator of pancreatic enzyme discharge. Our data also show that the stimulatory effect of PHA on pancreatic enzyme secretion can be blocked by urethane, an anaesthetic that is known to turn off the negative pancreatic feedback control of pancreatic function in rats.     

Glucocorticoids effects on exocrine pancreatic secretion in caerulein-induced acute pancreatitis in the rat.

The present work reports on exocrine pancreatic secretion in control rats, adrenalectomized rats and hydrocortisone-treated (10 mg/Kg/d) rats during 7 days, under normal conditions and after induction of acute pancreatitis with caerulein (20 micrograms/Kg) by 4 subcutaneous injections at hourly intervals. Pancreatic secretion was seen to be affected by the procedure of adrenalectomy, which led to a marked reduction in the secretion of proteins and amylase with respect to control values. This was probably due to the decrease occurring in the zymogen granules in the acinar cells of the exocrine pancreas, a phenomenon which also led to a decrease in pancreatic weight observed in these animals. Treatment with hydrocortisone induced a decrease in the secretion of proteins and amylase, as well as an increase in pancreatic weight. This agrees with the accepted hypothesis that large amounts glucocorticoids stimulate the synthesis and storage of proteins in the exocrine pancreas, reducing the secretory phase. The administration of high doses of caerulein under these conditions led to acute pancreatitis in the three groups of animals. This was paralleled by a dramatic decrease in protein and amylase secretion and by severe interstitial edema of the pancreas and by increases in serum amylase values. In the case of the animals treated previously with hydrocortisone, the latter were tripled with respect to the control animals. The conclusion is offered that since the storage of enzyme proteins is governed by glucocorticoids, which furthermore increase the sensitivity of the acinar cells to stimulation by secretagogues, the administration of these substances during the development of pancreatic lesions such as acute pancreatitis is highly compromising to the organism.     

Effects of pancreatic polypeptide on the pancreatic exocrine secretion stimulated by secretin and cholecystokinin in the conscious pig

Fourteen castrated male Large White pigs, weighing 42.5 +/- 1.0 kg, were fitted with pancreatic and duodenal fistulae for pancreatic secretion studies. Moreover, catheters were placed in a carotid artery for blood sampling and in a jugular vein for peptide infusion. Pancreatic juice was automatically restituted to the animals and continuously sampled for analysis on experimental days. Following an 8-day recovery period, perfusion studies were performed after an overnight fast. After a 30-min basal period, sustained pancreatic flow and protein output were obtained and maintained throughout the assay with secretin (36 pmol/kg/h) and CCK-8 (600 pmol/kg/h) infusion. Then, 200, 400, 600, 800 or 1200 pmol/kg/h of porcine pancreatic polypeptide (PP) were infused for 60 min. Secretin + CCK infusion was continued for 1 h after PP infusion was stopped. Each dose of PP was given on a separate day. Neither pancreatic flow nor bicarbonate output were affected whatever the dose of infused PP. On the contrary, protein concentration and output decreased with the lowest dose of PP (200 pmol/kg/h) and the diminution was more pronounced with the other doses. With 600 pmol/kg/h as well as with 800 and 1200 pmol/kg/h of PP, pancreatic protein output fell to about 20% of values obtained with secretin + CCK. Plasma levels of PP were below or similar to postprandial values for 200, 400 and 600 pmol/kg/h and they were significantly larger with 800 and 1200 pmol/kg/h. Protein concentration and output returned to values obtained with secretin + CCK infusion after cessation of PP infusion. In conclusion, porcine PP given in physiological doses to the pig decreases pancreatic protein output whereas pancreatic flow remains unaffected.     

Basal and spontaneous exocrine pancreatic secretion in conscious and anaesthetized chickens, Gallus domesticus

Basal exocrine pancreatic secretion was studied in anaesthetized and conscious chickens and spontaneous secretion was studied in anaesthetized chickens. Results are compared with those of other vertebrates to estimate the specific pattern of this secretion in birds. The flow of pancreatic juice was greater in conscious chickens than when anaesthetized (Table 1). Amylase activity was greater than that of the other species and was of the same order in anaesthetized and conscious birds (Table 1). A spontaneous exocrine pancreatic secretion was seen to remain after eliminating a large part of the tonic influences (Table 2).     

Effect of diversion of bile-pancreatic juice to the ileum on pancreatic secretion and adaptation in the rat

Cannulas were implanted to collect bile and pancreatic juice, and the collected secretions were pumped back into the intestine at the level of the duodenum or the proximal ileum. The effect of 6 days of such treatment on pancreatic secretion and on pancreatic growth was determined. The effect on pancreatic secretion was studied by measuring the pancreatic secretory response to a stimulus, provided by acute diversion of bile-pancreatic juice from the proximal intestine. Trophic effects were studied in a separate group of rats by measuring pancreatic weight, protein content, and chymotrypsin activity after an overnight fast. Stimulated pancreatic secretion was 2.1 times greater for protein output and 3.4 times greater for fluid output in rats with chronic diversion of bile-pancreatic juice to the ileum. Pancreatic weight, protein content, and chymotrypsin activity were increased 2.6, 2.9, and 4.8 times, respectively, by chronic diversion of bile-pancreatic juice to the ileum. These results indicate that pancreatic hypertrophy and hyperplasia reported in rats with bile-pancreatic duct transposition to the ileum are the result of loss of feed-back inhibition from bile-pancreatic juice in the proximal intestine.     

Effects of some gastrointestinal peptides on pancreatic growth in rats (preliminary results)

The purpose of this study was to estimate the effects of cholecystokinin (CCK), somatostatin (SS) pancreatic polypeptide (PP) and their interaction with each other, given them in single doses, on pancreatic secretion and pancreatic growth after long-term treatment in rats. The acute secretory effects of the above mentioned peptides were studied on conscious rats supplied with pancreatic, gastric and jugular vein cannulae. The pancreatic growth was characterized by measurements of pancreatic weight, desoxyribonucleic acid (DNA), protein, trypsin and amylase content after 5 days treatment. Amylase output was increased by caerulein alone, and given it in combination with somatostatin (SS), while its value decreased by SS alone. After 5 days treatment, the pancreatic weight, trypsin and amylase activity (hypertrophy) was increased by caerulein, and these values were not altered by S alone. In combinative administration of caerulein with somatostatin, the stimulatory effect by caerulein was decreased. PP given alone or in combination with caerulein decreased both the basal and stimulated amylase output. PP given for 5 days decreased pancreatic trypsin and amylase contents and counteracted the stimulatory effect by caerulein to these enzymes' contents. It has been concluded that: 1. caerulein stimulates both pancreatic enzyme secretion and pancreatic growth; 2. somatostatin inhibits the pancreatic secretion and caerulein induced pancreatic growth, but it does not affect the spontaneous growth of pancreas; 3. pancreatic polypeptide inhibits the pancreatic secretion and decreases pancreatic trypsin and amylase contents.     

Exposition of newborn rats to bacterial endotoxin impairs pancreatic enzyme secretion at adult age.

Lipopolysaccharide (LPS, endotoxin) is the component of the cellular wall of Gram negative bacteria. Endotoxemia (sepsis) could produce multiorgan failure and in the early period of life LPS are responsible for the changes of metabolism and for the reduction of protein synthesis. The influence of neonatal endotoxemia on the pancreas at adults has not been investigated yet. The aim of this study was to assess the pancreatic exocrine function in the adult rats which have been subjected, in the neonatal period of life, to chronic LPS pretreatment. LPS from E. coli or S. typhi at doses of 5, 10 or 15 mg/kg-day was administered intraperitoneally (i.p.) to the suckling rats (30 g) during 5 consecutive days. Three months later these animals (300 g) were equipped with pancreato-biliary fistulae for the in vivo secretory study. Amylase release from isolated pancreatic acini obtained from these rats was also assessed. Pancreatic tissue samples were taken for histological assessment and for the determination of gene expression for CCK1 receptor by RT-PCR. Pancreatic amylase secretions stimulated by caerulein or by diversion of pancreatic-biliary juice to the exterior (DBPJ) was significantly, and dose-dependently reduced in the adult rats which have been subjected in infancy to chronic pretreatment with LPS from E. coli or S. typhi, as compared to the untreated control. In these animals basal secretion was unaffected. In the rats pretreated with LPS in the suckling period of life caerulein-induced amylase release from isolated pancreatic acini was significantly decreased, as compared to the untreated with LPS control. This was accompanied by dose-dependent reduction of mRNA signal for CCK1 receptor on pancreatic acini. Neonatal endotoxemia failed to affect significantly pancreatic morphology as well as plasma amylase level in the adult rats. We conclude that neonatal endotoxemia reduces gene expression for CCK1 receptor and could produce impairment of the exocrine pancreatic function at adult age.     

Compensation of exocrine pancreatic insufficiency during its partial, subtotal and total resection

Chronic experiments on dogs have shown that the damage of extra-secretory pancreatic function by duct ligation caused marked compensatory changes of stomach function. The increase in gastric juice secretion and gastric juice proteolytic activity was accompanied by the reduction in its acidity. In addition to quantitative changes, qualitative shifts were revealed (amylolytic activity in strongly acid pH-reaction), never observed in the gastric juice of intact animals. Partial pancreas resection (up to 75%) both in control and test animals 10-14 months after pancreatic duct ligation was not accompanied by significant changes in gastric juice secretion. Total pancreas resection in dogs with previous pancreatic duct ligation caused neither prompt animal death, as in the control, nor the inhibition of compensatory reactions of gastric juice secretion.     

Response of rat exocrine pancreas to high-fat and high-carbohydrate diets

Intake of diets with high fat content is a risk factor for acute pancreatitis and pancreatic cancer. The underlying mechanisms leading to the development of these diseases due to high fat intake are currently unknown. The current study was designed in rats to determine the physiologic and pathological consequences of a highfat diet that contained excess amounts of cottonseed oil or a high-carbohydrate diet that contained high amounts of sucrose on the exocrine pancreas. Rats were maintained on the diets for 4 weeks, and a cannula was inserted into the right jugular vein and one into the pancreatic duct for collection of pancreatic juice. Volume of the pancreatic juice and concentrations of amylase, lipase, and trypsinogen in the pancreatic juice were measured before and after infusions of CCK-8. Results showed that basal and CCK-stimulated pancreatic outputs of volume, amylase and lipase but not trypsinogen, were significantly elevated in intact rats given a high-fat diet when compared with rats given a high-carbohydrate diet. Forty-eight hours later, rats were sacrificed, and parts of the pancreas were removed for isolation of pancreatic acinar cells and for histopathologic studies. Pancreatic acini isolated from rats on a high-fat diet showed significantly lower basal and CCK-stimulated amylase release when compared with those on a high-carbohydrate diet. Histology of the pancreas of rats on a high-carbohydrate diet appeared normal; however, the pancreas of rats on high-fat diet showed significant alterations in exocrine pancreas. These results showed abnormalities in the exocrine pancreas of rats on a high-fat diet, that were not found in rats on a high-carbohydrate diet; further, they support the contention that a high-fat diet has a deleterious effect on the pancreas.     

Effect of a new CCK-A receptor antagonist,dexloxiglumide, on the exocrine pancreas in the rat

The effect of dexloxiglumide, a new potent cholecystokinin (CCK) antagonist, on pancreatic enzyme secretion and growth was studied in the rat. Pancreatic exocrine secretion was studied both in vitro (isolated and perfused pancreatic segments) and in vivo (anaesthetized animals with cannulation of the common bile duct) whereas the trophic effect was investigated after short-term (7 days) administration of the CCK-agonist, caerulein, or camostate (a potent trypsin inhibitor), with or without dexloxiglumide. CCK-8 stimulated amylase release from in vitro pancreatic segments in a concentration-dependent manner. Dexloxiglumide displaced the concentration response curves to CCK-8 to the right without affecting the maximum response, suggesting a competitive antagonism. The Schild plot analysis of data gave a straight line with a slope (0.90±0.36) not significantly different from unity. The calculated pA₂ for dexloxiglumide was 6.41 ± 0.38. In vivo experiments confirmed results from in vitro studies since intravenous dexloxiglumide reduced pancreatic exocrine secretion induced by submaximal CCK-8 stimulation (0.5 nmol/kg/h) in a dose-dependent manner, the ID₅₀ being 0.64 mg/kg. Both exogenous and endogenous (released by camostate) CCK increased the weight of the pancreas, the total pancreatic protein and DNA, trypsin and amylase content. Dexloxiglumide (25 mg/kg), administered together with caerulein (1 μg/kg), reduced the peptide-induced increase in pancreatic weight, protein and enzyme content. Similarly, when dexloxiglumide was given together with camostate (200 mg/kg), all the observed changes were reduced by concomitant administration of the antagonist. These results demonstrate the ability of dexloxiglumide to antagonize the effects of CCK on pancreatic secretion and growth, suggesting that this compound is a potent and selective antagonist of CCK-A-receptors in the pancreas.     

Morphological changes in the rat exocrine pancreas after pancreatic duct ligation

In the present study, morphological changes of the exocrine pancreas in rats after pancreatic duct ligation were examined with light microscopy (hematoxylin-eosin, TUNEL, and PCNA staining) and scanning electron microscopy in order to elucidate the effects of increased pancreatic duct pressure. On the fifth day after pancreatic duct ligation, ductular proliferation, periductal fibrosis, and disappearance of acini were observed. TUNEL and PCNA staining demonstrated many apoptotic acinar cells and proliferating ductal cells immediately after ligation, which reached a maximal number on the 2nd or 3rd day. Tortuous or helical interlobular pancreatic ducts with inner surfaces containing many crater-like depressions and long cilia were found after ligation. These changes were almost identical to those observed in the pancreatic tissue of model chronic pancreatitis rats, WBN/Kob rats, and stroke-prone spontaneously hypertensive (SHRSP) rats. In summary, the morphological changes observed after pancreatic duct ligation were similar to those of chronic pancreatitis, therefore, the characteristic changes of pancreatic ducts observed in chronic pancreatitis may be caused by increased pancreatic duct pressure.     

Comparison of the effects on inhibition of cyclooxygenase and thromboxane synthetase on renal excretion and haemodynamics in rats of different ages

Effects of the cyclooxygenase inhibitors indomethacin, naproxen and the thromboxane synthetase inhibitor imidazole on renal sodium water and p-aminohippurate excretion were investigated in sodium loaded conscious rats of different ages. Renal and intrarenal blood flow were studied in anaesthetized adult rats. Indomethacin and naproxen reduced PAH excretion in 5- and 10-day-old rats but not in rats of older ages. Imidazole failed to influence PAH-excretion in young animals. The excretion of PAH was decreased in adult rats at 10 and 60 min following imidazole administration, but not after longer time interval (120 min). Following indomethacin and naproxen administration urine output was decreased in 5-, 10- and 15-day-old rats, but not in rats of older ages. Effects of imidazole on electrolyte excretion can be demonstrated in adult rats only. Cardiac output was not altered by the three drugs. Blood pressure was elevated after indomethacin, but remained unchanged after naproxen and imidazole treatment. Renal and cortical blood flow remained unaltered and no redistribution was seen in intrarenal blood flow after indomethacin, naproxen and imidazole administration. The experimental data suggest that prostaglandins and thromboxanes are involved in the regulation of kidney function, but prostaglandins in the rat--in contrast to the dog--do not seem to play a major role in the regulation of renal vascular tone in adult animals.     

Stimulation of pancreatic secretory process in the rat by low-molecular weight proteinase inhibitor

Summary Application of a single dose of a new type of proteinase inhibitor camostate (FOY-305) via orogastric tube was used in rats to study the dose-response relationship of resulting pancreatic stimulation. Doses up to 10 mg/ kg failed to elicit any response, while significant decrease in enzyme content and increase in serum CCK-levels were observed with doses ranging from 25 to 400 mg/kg. A single dose of 100 mg/kg was selected for a time-sequence analysis, which revealed a 60 to 70% depletion of enzyme stores persisting over 6 h and reverting to control levels by 12 h. Peak increases in serum CCK-levels (15-fold above the elevation observed after regular food intake) were found after 30 min and persisted as an 8-to 10-fold elevation for at least 3 h, then declined to control levels by 9 h. This prolonged endogenous hormone release and resulting pancreatic stimulation were also verified in a separate group of animals in which volume, protein, and enzyme output were measured after cannulation of the pancreatic duct. While volume secretion was not altered by feeding a single dose of 100 mg/kg FOY-305, protein and enzyme output increased 2-to 3-fold over a period of 7 h. Fine-structural analysis of the pancreas demonstrated efficient depletion of zymogen granules from acinar cells with all doses between 50 and 400 mg/kg, accompanied by the appearance of membrane material in the acinar lumina at 3 and 6 h. The same transient increase in the number of lysosomal bodies predominantly containing mitochondria with all doses above 50 mg/kg was interpreted as increased organelle turnover due to persisting hormonal stimulation.Supported by a grant from the Deutsche Forschungsgemeinschaft (Ke 113/15-1/2)     

Calcium requirements in the action of cholecystokinin-pancreozymin on pancreatic acinar cell metabolism.

The present study utilized ionophore A23187 to determine the role of Ca²⁺ in pancreatic acinar cell metabolism. The ionophore A23187 in the presence of EGTA increased efflux of Ca²⁺ from the rat pancreatic fragments. Ionophore and CCK-PZ were equally effective in the presence of extracellular Ca²⁺ in stimulating ¹⁴C-labeled protein secretion. The ionophore decreased synthesis of new protein more effectively than CCK-PZ in the presence of extracellular Ca²⁺. The effect of ionophore and CCK-PZ in combination was greater than either agent alone. Phospholipid labeling was not stimulated by A23187 in the presence of extracellular Ca²⁺ in contrast to CCK-PZ. With CCK-PZ, the effect was dependent on the concentration of extracellular Ca²⁺. Protein phosphorylation was stimulated ～ 109% by CCK-PZ and ～ 39% by ionophore. CCK-PZ stimulated protein phosphorylation in the 100,000 g supernatant whereas A23187 was ineffective. Ionophore A23187 inhibited glucose oxidation whereas CCK-PZ stimulated glucose oxidation. These data suggest that more than one kinase system might be involved in metabolic responses to hormonal stimulation of the pancreas viz. a phosphorylase kinase may be directly activated by Ca²⁺ causing protein discharge whereas other kinase system may require binding of the hormone to receptor leading to other events besides protein discharge.