Acute administration of intact parathyroid hormone but not its amino-terminal fragment stimulates volume of pancreatic secretion.

Chronic renal failure is associated with structural and functional abnormalities of the exocrine system of the pancreas. Certain data suggest that the excess parathyroid hormone (PTH) in these patients may participate in the genesis of these pancreatic derangements. However, direct evidence that PTH exerts a direct effect on the exocrine pancreatic system is not well documented. The present study examined the effects of the intact molecule (1-84 PTH) and of the amino-terminal fragment (1-34 PTH) of the hormone on the basal output of pure pancreatic juice (PPJ) volume and pancreatic protein secretion in the rat. 1-84 PTH but not 1-34 PTH significantly (p less than 0.01) stimulated the output of PPJ volume without an effect on protein secretion. The magnitude of this stimulatory effect of 1-84 PTH depended on the dose of the hormone administered, and it was related to its biological activity, since inactivation of PTH abolished its action on the output of PPJ volume. The simultaneous administration of the calcium channel blocker, verapamil, reduced but did not abolish the stimulatory effect of PTH on the volume of PPJ output. The data demonstrate that: (1) the ductal cells of the pancreatic acini are targets for PTH and (2) the action of the hormone on these cells is mediated, at least in part, via PTH-induced entry of calcium into the target cells.

Localization of monoclonal antibody TNT-1 in experimental kidney infarction of the mouse.

An experimental kidney infarction model was developed in the mouse to study the uptake of a radiolabeled monoclonal antibody previously shown to bind to degenerating cells in malignant tumors. To determine if this approach is applicable to normal tissue and cell degeneration, kidney infarction was produced by clamping the mouse renal artery for 3 h using surgical procedures. Various groups of mice were injected with 131I-labeled TNT-1 F(ab')2 monoclonal antibody directed against nuclear histone antigens at varying intervals after surgery. Imaging, biodistribution, autoradiography, and histological studies were performed on each group of mice, including sham-operated controls, to quantitate the level of binding and localize the uptake of label in clamped and unclamped (contralateral) kidneys. As additional controls, clamped mice were administered radiolabeled irrelevant monoclonal antibody Lym-1 or mouse albumin. The results showed a marked selective uptake of radiolabeled TNT-1 F(ab')2 in the injured clamped kidney compared with the untreated kidney and other normal organs of the mouse. These studies define a model of normal organ necrosis that may be useful for study of the kinetics of antibody uptake in infarcted tissues.

[D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C antagonizes neuromedin C-stimulated amylase release by acini isolated from the rat pancreas.

Two novel neuromedin C analogs [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C and [Leu9-psi-CH2NH-Leu10]neuromedin C, were synthesized by rapid solid phase methods and examined for their abilities to inhibit neuromedin C-stimulated amylase release by isolated rat pancreatic acini. Both analogs significantly inhibited maximally stimulated amylase release by neuromedin C in a dose-dependent manner with maximal inhibition seen at concentrations of 100 and 300 microM of [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C and [Leu9-psi-CH2NH-Leu10]neuromedin C, respectively. The IC50 (concentration required to half-maximally inhibit neuromedin C-stimulated amylase release) was 1.5 microM for [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C compared to a 13.4 microM IC50 for [Leu9-psi-CH2NH-Leu10]neuromedin C. The [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C analog produced a parallel rightward shift in the neuromedin C dose-response curve and Schild plots of the inhibition data gave a slope of 0.969 +/- 0.121 and a pA2 (apparent affinity for the acinar cell receptor in terms of neuromedin C receptor-stimulated amylase release) of 100 nM. While [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C significantly inhibited both neuromedin B- and gastrin releasing peptide-stimulated amylase release, the analog did not inhibit amylase release in response to either cholecystokinin octapeptide, vasoactive intestinal peptide, substance P, carbamylcholine, the Ca2+ ionophore A23187, forskolin, or 8-bromo-cyclic AMP. The results demonstrate that [D-Ala1, Leu9-psi-CH2NH-Leu10]neuromedin C is a potent, specific, and competitive antagonist for neuromedin C and peptides of the gastrin releasing peptide family and may serve as a useful molecule for exploring the physiological role of these peptides.

Chronic administration of a potent cholecystokinin receptor antagonist, L-364,718, fails to inhibit pancreas growth in preweanling rats.

We examined whether endogenous cholecystokinin (CCK) is involved in growth of the preweanling rat pancreas. Twice daily for 14 days, 7-day-old neonatal rats received an oral gavage of either 2.5 mg/kg or 5.0 mg/kg of the potent and specific CCK receptor antagonist L-364,718 (the 2.5 mg/kg dose of antagonist was shown in the present study to abolish totally the pancreas growth-promoting effects of exogenously administered caerulein (CR) in neonatal rats). Control pups received oral gavages of the L-364,718 vehicle alone. The final body weights, pancreas weights, total pancreatic DNA contents, and total pancreatic protein contents did not differ significantly between the 21-day-old control pups and the 21-day-old pups that were pretreated for 14 days with either the low or the high doses of L-364,718. These findings suggest that endogenous CCK is not required for growth of the neonatal rat pancreas.

The effects of nafamostat mesilate (FUT-175) on caerulein-induced acute pancreatitis in the rat.

We examined the ability of a highly potent synthetic protease inhibitor, nafamostat mesilate (FUT-175), to protect the rat pancrease against AP induced by a supramaximal dose of caerulein (CR). Rats received a 6-h, continuous intravenous (iv) infusion of either CR alone or CR + a 6-h infusion of either 2.5, 5.0, 10.0, 25.0, or 50.0 mg of FUT-175/kg/h. Pancreas weights and serum chymotrypsinogen concentrations were significantly elevated by approximately 85 and 75%, respectively, over values in saline infused rats. Pancreas weights in rats treated with CR + FUT-175 at doses from 2.5-25.0 mg/kg/h were significantly reduced by approximately 20% compared to rats given CR along, and histology showed a reduction in the extent and size of acinar cell vacuolization and reduced interstitial edema compared to rats treated with CR alone. Serum chymotrypsinogen concentrations in rats treated with CR and either 5.0 or 10.0 mg of FUT-175/kg/h were significantly lower than in rats given CR alone. Significant mortality occurred in rats infused with FUT-175 at doses of either 25.0 or 50.0 mg of FUT-175/kg/h. These data indicate that serine proteases appear to be involved in the pathogenesis of CR induced AP in rats and that FUT-175 administered in low doses (2.5-10.0 mg/kg/h) provides significant protection against this form of pancreatitis.

Pancreatic exocrine function in unconscious rats treated with submaximal, maximal, and supramaximal doses of bombesin tetradecapeptide.

Supramaximal stimulation of the rat pancreas in vivo with caerulein elicits a sharp decline in pancreatic juice volume and protein outputs and initiates acute edematous pancreatitis within 30 min. Because of the similar effects of caerulein and bombesin on pancreatic exocrine function, we examined in unconscious rats (a) the effects of a continuous, 4-h intravenous infusion of varying doses (0.2-40.0 nmol/kg/h) of bombesin on pancreatic juice volume and protein output, and (b) whether supramaximal doses of bombesin produce acute edematous pancreatitis. A maximal, fivefold and 17-fold rise in pancreatic juice volume and protein output was achieved with intravenous doses of 1.0 and 4.0 nmol of bombesin/kg/h, respectively. Pancreas weights in rats infused with bombesin as high as 40.0 nmol/kg/h were not significantly different from control animal values (no bombesin infusion) and serum amylase concentrations were only moderately (twofold) elevated over control values in rats i.v. infused with 4.0-40.0 nmol of bombesin/kg/h. The pancreas in rats treated with the highest dose of bombesin (40.0 nmol/kg/h) revealed sparsely scattered microvacuoles in a few acinar cells and minor evidence of interacinar edema. It is concluded that supramaximal stimulation of the rat pancreas in vivo with bombesin fails to elicit acute edematous pancreatitis and appears to be related to the ability of bombesin, in contrast to supramaximal doses of caerulein, to continuously stimulate maximal pancreatic juice secretion.

Evidence against cholecystokinin mediation of basal and bombesin-stimulated pancreatic secretion in the rat.

Studies in dogs suggest that bombesin-stimulated pancreatic exocrine function is mediated via endogenous cholecystokinin. We studied (a) the short-term effects of bombesin on pancreatic juice volume and protein output in unconscious rats and (b) whether a potent cholecystokinin-receptor antagonist, L-364,718, affects the pancreatic exocrine response to bombesin. A 4-h i.v. infusion of low-dose (0.2 nmol/kg.h) or high-dose (1.0 nmol/kg.h) bombesin elicited significant increases in pancreatic juice volume and protein output, which were unaltered by treatment with L-364,718 at a dose capable of fully suppressing cholecystokinin-octapeptide-stimulated pancreatic juice volume and protein output. We conclude that the effects of exogenously administered bombesin on the exocrine pancreas in the rat are not mediated via release of endogenous cholecystokinin.

Allopurinol attenuates caerulein induced acute pancreatitis in the rat.

Oxygen derived free radicals have been implicated in the pathogenesis of acute pancreatitis in numerous animal models of the disease. The xanthine oxidase inhibitor allopurinol has been shown to attenuate pancreatic damage in canine and mouse models of acute pancreatitis presumably by preventing the generation of cytotoxic superoxide anions. We therefore examined whether allopurinol could attenuate pancreatic injury in conscious rats with caerulein induced acute pancreatitis. A continuous intravenous infusion of allopurinol (20 mg/kg/h) for six hours along with an acute pancreatitis producing dose of caerulein (10 micrograms/kg/h) reduced pancreas weights by approximately 45% and serum amylase concentrations by approximately 60% compared with rats intravenously infused with either caerulein alone or caerulein plus a lower dose (10 mg/kg/h) of allopurinol. We conclude that the generation of oxygen derived free radicals via pancreatic xanthine oxidase represents an early and perhaps pivotal mechanism in the pathogenesis of acute pancreatitis.

A possible zymogen self-destruct mechanism preventing pancreatic autodigestion.

Incubation at 37 degrees C of human cationic trypsinogen purified by PAGE electrophoresis, results in development of proteolytic activity (enzyme Y) capable of rapidly degrading cationic and anionic trypsinogens to inert products. Enzyme Y appears to be a serine protease with a molecular weight of about 20,000 daltons and is different from any of the known pancreatic enzymes. The active enzyme may be derived from trypsinogen itself or a hitherto unrecognized precursor contaminating the trypsinogen fraction used in this work. Appearance of enzyme Y activity seems to be associated with the presence of traces of free trypsin. Enzyme Y possesses insignificant or no activity when tested with a variety of synthetic trypsin, chymotrypsin and other protease substrates. It is not inactivated by the specific trypsin and chymotrypsin inhibitors TLCK and TPCK, but its activity is reduced gradually by increasing concentrations of pancreatic secretory trypsin inhibitor. Ca2+ concentrations greater than 3 mM strongly inhibit enzyme Y, and diisopropylfluorophosphate completely inactivates it. The enzyme is stable when incubated at pH 1.9 and 37 degrees C for 30 min and its activity is not abolished by treatment with Hg2+. When added to pancreatic juice with low inhibitor content it causes rapid inactivation of zymogens without significant release of active enzymes or reduction of pancreatic trypsin inhibitor. Its physiological role may be perceived as a second line of defense against premature intrapancreatic activation of zymogens. Enzyme Y activity may be generated when trypsin inhibitor, the first line of defense, is sufficiently depleted by complex formation with inappropriately released trypsin to permit dissociation of a small amount of trypsin from this complex. This in turn may lead to activation of enzyme Y and inactivation of the zymogens of pancreatic proteases.

Effects of L-364,718, a new cholecystokinin receptor antagonist, on camostate-induced growth of the rat pancreas.

Chronic feeding of rats with camostate results in pancreatic hypertrophy or hyperplasia, or both. Previous studies suggest that this effect of camostate occurs via an increase in endogenous cholecystokinin due to an enteral feedback mechanism involving the inhibition of trypsin in the duodenum. Studies employing proglumide, a weak and relatively nonspecific cholecystokinin antagonist, have failed to fully abolish camostate-induced pancreas growth. We examined the effects of L-364,718, a new and highly potent cholecystokinin receptor antagonist, on camostate-induced pancreas growth in rats. The pancreas weights and the concentrations of ribonucleic acid, protein, and chymotrypsinogen in the pancreas of rats treated with camostate alone were significantly elevated over those of controls. These effects of camostate were completely abolished in rats treated with camostate + L-364,718. The pancreas weights and the concentrations of deoxyribonucleic acid and ribonucleic acid in the pancreas of rats treated with L-364,718 alone were significantly lower than values in control rats. These data indicate that camostate-induced pancreas growth in rats appears to be dependent on the actions of endogenous cholecystokinin and that cholecystokinin may play a role in the maintenance of pancreatic growth in normal rats.

Asperlicin, a nonpeptidal cholecystokinin receptor antagonist, attenuates sodium taurocholate-induced acute pancreatitis in rats.

Asperlicin (ASP), a new, nonpeptidal cholecystokinin (CCK) receptor antagonist isolated from the fungus Aspergillus alliaceus, has an affinity that is 300-400 times greater than that of proglumide for gallbladder, ileal, and pancreatic CCK receptors. The long in vivo half-life and high selectivity for peripheral CCK receptors make ASP suitable for investigations on the physiological and pharmacological actions of CCK. Endogenous CCK has been postulated to participate in the pathogenesis of acute hemorrhagic pancreatitis (AHP) in rats and mice. We examined the effects of ASP in rats on the early course (6 h) of AHP induced by a retrograde infusion of sodium taurocholate (NaTC) into the common bile-pancreatic duct. An i.v. bolus injection of ASP (either 10 mg/kg or 30 mg/kg) in dimethyl sulfoxide (DMSO) given 1 h prior to AHP induction failed to significantly alter pancreas weights, serum amylase concentrations, or pancreatic histopathology when compared with AHP control rats treated with vehicle alone. However, rats given 2 i.p. injections of ASP (either 20 mg/kg/injection or 40 mg/kg/injection) in DMSO: olive oil 1 h before and 2 h after induction of AHP exhibited significantly reduced serum amylase concentrations. Additionally, rats given the high dose i.p. injections of ASP also had significantly reduced pancreas weights and less severe pancreas histopathology compared with AHP control animals. These data indicate that endogenous CCK participates in the pathogenesis of NaTC-induced AHP in the rat.

Gabexate mesilate (FOY) protects against ceruletide-induced acute pancreatitis in the rat.

Acute pancreatitis (AP) is believed to result from intraparenchymal activation of trypsin and other digestive enzymes within the pancreas followed by autodigestion of the gland. Gabexate mesilate (FOY), a synthetic guanidino acid ester exhibiting potent and versatile inhibitory actions on a number of proteinases (e.g., trypsin, kallikrein, C1-r, C1 esterase, plasmin, thrombin, phospholipase A2), was examined for its ability to protect the rat pancreas against development of AP induced by pharmacological doses of ceruletide (CRT). Rats were i.v. infused for 6 h with either CRT (5 micrograms/kg/h) or CRT + FOY (50 mg/kg/h). In FOY-treated rats the serum amylase and trypsinogen concentrations were reduced by 60 and 80%, respectively, compared to rats infused with CRT alone. Histologically, the extent of acinar cell vacuolization in the pancreas was significantly reduced and interstitial edema, although not assessed by quantitative morphometric techniques, appeared to be qualitatively lessened in the FOY-treated rats. The ability of FOY to inhibit significantly AP produced by supramaximal doses of CRT, coupled with its inhibitory properties on components of the coagulation and complement cascades, stress the importance of continued research on this compound as a potential therapeutic agent for treatment of AP and its systemic sequelae.

Ceruletide-induced acute pancreatitis in the dog and its amelioration by exogenous secretin.

Large pharmacological doses of ceruletide administered to conscious dogs by intravenous (i.v.) infusion uniformly induce a severe acute necrotizing pancreatitis within 4 h. High-dose i.v. secretin administered for a period of 24 h after cessation of ceruletide infusion resulted in a significant amelioration of the acute pancreatitis compared to non-secretin-treated dogs with acute pancreatitis. Light microscopy of the pancreas in secretin-treated dogs revealed a significant decrease in edema, polymorphonuclear leukocyte infiltration, cell necrosis and acinar cell vacuolization. Serum amylase levels in secretin-treated dogs were significantly decreased compared to non-secretin-treated dogs. The results of this study suggest that high-dose i.v. secretin exerts a beneficial effect on pre-established, ceruletide-induced acute pancreatitis in dogs.

Partial restoration of pancreatic function by exogenous secretin in rats with ceruletide-induced acute pancreatitis.

Pharmacological doses of ceruletide administered intravenously to unconscious rats uniformly induces acute pancreatitis (AP) as well as a striking reduction in pure pancreatic juice (PPJ) and protein output. High-dose intravenous secretin administered to rats with ceruletide-induced AP effects a reestablishment of PPJ flow and a significant increase in PPJ protein output. Light microscopy of the pancreas in ceruletide-induced AP rats revealed marked acinar cell vacuolization and intense interstitial edema. By contrast, pancreatic histology in AP rats treated with high-dose secretin revealed a distinct lessening of acinar cell vacuolization and interstitial edema. We have established that high-dose intravenous secretin given to rats with ceruletide-induced AP is (1) not harmful, (2) reestablishes PPJ flow and evokes a partial restoration of protein output, and (3) appears to reduce pancreatic histopathology when compared to non-secretin-treated rats with AP.

Death due to acute pancreatitis. A retrospective analysis of 405 autopsy cases.

A large retrospective autopsy study of patients was analyzed to evaluate the major etiologic and pathologic factors contributing to fatal acute pancreatitis (AP). From an autopsy population of 50,227 patients, 405 cases were identified where AP was defined as the official primary cause of death. AP was classified according to morphological and histological, but not biochemical, criteria. Patients with AP died significantly earlier than a control autopsy population of 38,259 patients. Sixty percent of the AP patients died within 7 days of admission. Pulmonary edema and congestion were significantly more prevalent in this group, as was the presence of hemorrhagic pancreatitis. In the remaining 40% of patients surviving longer than 7 days, infection was the major factor contributing to death. Major etiologic groups in AP were chronic alcoholism; postabdominal surgery; common duct stones; a small miscellaneous group including viral hepatitis, drug, and postpartum cases; and a large idiopathic group comprising patients with cholelithiasis, diabetes mellitus, and ischemia. The prevalence of established diabetes mellitus in the AP group was significantly higher than that observed in the autopsy control series, suggesting that this disease should be considered as an additional risk factor influencing survival in AP. Pulmonary complications, including pulmonary edema and congestion, appeared to be the most significant factor contributing to death and occurred even in those cases where the pancreatic damage appeared to be only moderate in extent. Emphasis placed on the early recognition and treatment of pulmonary edema in all cases of moderate and severe AP should contribute significantly to an increase in survival in this disease.

Influence of nutritional status on circulatory ribonuclease C levels in patients with cancer.

The influence of a variety of clinical and biochemical parameters on the activities in serum of ribonuclease (RNAse) selective for polycytidylic acid (RNAse C) were examined in 90 adult patients with cancer. The clinical data base determined on each patient included: RNAse C level, carcinoembryonic antigen (CEA) level, age, sex, race, presence (or absence of metastases, type of cancer, site of metastasis, renal function blood urea nitrogen [BUN], creatinine), hepatic function (bilirubin, alkaline phosphatase), and nutritional status (percent ideal body weight, percent weight loss, and albumin). Common tumor types studied included: colon (21), lung (18), breast (15), and hepatocellular carcinoma (10). For comparison, 175 nonmalignant control patients were studied to establish the normal range for RNAse. In patients with cancer, RNAse levels were increased in 57% and CEA levels were above 10 ng/dl in 36%. Although patients with BUN greater than 25 mg/dl or creatinine greater than 1.5 mg/dl were not entered on the study, nonetheless, RNAse was significantly (P less than 0.05) associated with both BUN and creatinine. Nutritional status also had an important influence on RNAse levels as both percent weight loss and percent ideal body weight were significantly (P less than 0.05) associated with circulatory RNAse: weight loss resulted in higher RNAse levels. These results account in part for the increased RNAse levels seen in those malignant conditions such as pancreatic and lung cancer commonly associated with weight loss in advanced stage. The possibility that circulatory RNAse C determination will provide a sensitive means for assessing nutritional status in cancer patients will require prospective evaluation.

Effects of chronic alcohol abuse on exocrine pancreatic secretion in man.

The effect of chronic alcohol abuse on the secretion of pancreatic exocrine proteins was studied. Pure pancreatic juice (PPJ) was obtained by endoscopic cannulation of the pancreatic duct from 21 healthy, nonalcoholic volunteers and 25 chronic alcoholics. Peak concentration and output of total proteins after sequential stimulation with secretin and cholecystokinin was elevated significantly in chronic alcoholics when compared to nonalcoholic subjects. The most striking change in the secretory proteins investigated was exhibited by the trypsinogens. Although the concentrations of all three trypsinogen variants were elevated significantly in PPJ of chronic alcoholics, most of the increase resulted from an approximately fivefold increase of the anionic variant, suggesting nonparallel alterations in the synthesis of pancreatic exocrine proteins. Whereas the ratio of cationic-anionic trypsinogen in the control group was consistently greater than one, it was, without exception, below one in the chronic alcoholics group. As there was no significant increase in trypsin inhibitor in PPJ of alcoholics, the ratio of trypsinogen-trypsin inhibitor showed a highly significant increase in this group. This distortion of the normal ratio in favor of trypsinogen may facilitate premature activation of pancreatic zymogens as postulated in acute pancreatitis. The concentrations of other zymogens and lysosomal hydrolases in PPJ of chronic alcoholics showed small, but not significant, increases, with the exception of leucine naphthylamidase which was significantly elevated. Nonparallel secretion of some exocrine proteins previously described in healthy nonalcoholic subjects was affected selectively by chronic ethanol ingestion. Thus, in chronic alcoholics the secretory kinetics of trypsinogen and chymotrypsinogen were altered, but trypsin inhibitor secretion remained apparently unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Pure human pancreatic juice directly enhances uptake of cobalamin by guinea pig ileum in vivo.

Although pancreatic enzymes clearly degrade R binder, a nonintrinsic factor binder, the full scope of the pancreatic role in cobalamin absorption remains the subject of debate. Therefore the direct effect of pure human pancreatic juice (PPJ) on ileal cobalamin absorption in the absence of intrinsic factor was studied. PPJ significantly enhanced cobalamin uptake in guinea pig ileal loop perfused in vivo. It did not do so in the jejunum. This PPJ activity in the ileum was further stimulated by enteropeptidase and inhibited by aprotinin. The intestinal mucosa remained intact during our study by morphologic and inulin clearance criteria and behaved normally with respect to intrinsic factor and nonintrinsic factor binders. Since no intrinsic factor was present in the perfusate, PPJ must directly enhance cobalamin uptake by the ileum, perhaps promoting cobalamin attachment to receptor sites for subsequent transport by intrinsic factor. PPJ thus seems to affect cobalamin absorption at several levels. Previous studies have established its interaction with luminal R binders and with bile. The findings now indicate that pancreatic juice may have an additional, more direct role in promoting cobalamin absorption in the ileum.

Double-contrast barium meal and upper gastrointestinal endoscopy. A comparative study.

One hundred randomly selected inpatients were examined with both double-contrast barium meal and endoscopy in a blinded prospective fashion. All studies were done by staff personnel, with equal clinical information available to both the radiologist and endoscopist. The final diagnosis was made by a review committee of participating radiologists and endoscopists. Endoscopy was more sensitive (92% versus 54%, p less than 0.001) and specific (100% versus 91%, p less than 0.05) than the double-contrast barium meal. Both procedures significantly affected the clinical outcome of the patient, the effect of endoscopy being significantly greater than that of the double-contrast barium meal. Although errors with the barium study related predominantly to an inability to show subtle lesions, poor patient cooperation and perceptual and technical failures were additional significant factors. Endoscopy is recommended for certain groups of patients.