Neurochemical regulation of Aedes aegypti salivary gland function

The salivary gland of hematophagous arthropods is critical for blood meal acquisition, blood vessel localization, and secretion of digestive enzymes. Thus, there is significant interest in the regulation of salivary gland function and mechanisms driving the secretion of saliva and digestive proteins. We aimed to gain a broader understanding of the regulatory role of aminergic, cholinergic, and octopaminergic neuromodulators to saliva and protein secretion from the female A. aegypti salivary gland. Quantification of saliva after injection with neuromodulators showed that dopamine, serotonin, and pilocarpine increased the secretory activity of the salivary gland with potency rankings dopamine = serotonin > pilocarpine. No change in saliva secretion was observed with octopamine or ergonovine, which indicates the A. aegypti salivary gland may be regulated by dopaminergic, serotonergic, and cholinergic systems, but are not likely regulated by octopaminergic or tryptaminergic systems. Next, we studied the regulatory control of dopamine-mediated salivation. Data indicate extracellular calcium flux, but not neural function, is critical for dopamine-mediated salivation, which suggests epithelial transport of ions and not neuronal control is responsible for dopamine-mediated salivation. For regulation of protein secretion, data indicate dopamine or serotonin exposure facilitates amylase secretion, whereas serotonin but not dopamine exposure increased apyrase concentrations in the secreted saliva. General immunoreactivity to anti-rat D1-dopamine receptor antibody was observed, yet immunoreactivity to the anti-rat D2-receptor antibody was identified in the proximal regions of the lateral lobes and slight immunoreactivity in the distal portion of the lateral lobe, with no expression in the medial lobe.

Effect of levetiracetam drug on antioxidant and liver enzymes in epileptic patients: case-control study

BACKGROUND

There is a limited amount of data regarding levetiracetam (LEV), an antiepileptic drug.

OBJECTIVE

This study was conducted to assess the effect of LEV on antioxidant status and liver enzymes.

METHODS

In this case-control study, 33 epileptic patients under treatment with LEV for at least 6 months were compared with 35 healthy subjects. We measured serum total antioxidant capacity (TAC), salivary superoxide dismutase (SOD), alanine aminoteransferase (ALT), and aspartate aminoteransferase (AST) levels in both groups. Dietary intakes were collected using a Food Frequency Questionnaire (FFQ).

RESULT

The level of TAC in the healthy subjects was significantly higher than it was in the patients (P=0.02), but the mean of ALT (P=0.02) and AST (P=0.03) was significantly higher in the patients in comparison with the controls. Mean salivary SOD showed no difference between the two groups. In the patients, the duration of drug use was inversely correlated with serum TAC (p=0.04) and had a direct correlation with ALT (p=0.01) and AST (p=0.03.).

CONCLUSION

The results of our study indicated that LEV increased liver enzymes Also, treatment with this drug did not improve oxidative stress, but this could be due to the different in the dietary antioxidant intake. Routine screening of the liver and antioxidant enzymes in patients with chronic use of LEV is recommended.

Comparison of serum amylase level between dipeptidyl peptidase-4 inhibitor and GLP-1 analog administration in patients with type 2 diabetes mellitus

We monitored serum amylase level in patients with type 2 diabetes mellitus (T2DM) prescribed either dipeptidyl peptidase-4 inhibitor or GLP-1 analog (GLP-1 group) as monotherapy. Patients were treated for a 36-month period. All subjects were non-smoker and did not take any alcoholic beverages. Forty-nine patients were prescribed DPP4is (DPP4i group), and 9 patients were prescribed GLP-1 analogs (GLP-1 group). The median of serum amylase levels in DPP4is group was 73 U/mL and the median of serum amylase levels in GLP-1 analog group was 76. Thus, there was no statistical significance between the two groups. However, the increased serum amylase levels in the three patients were observed only in the DPP4is group. One strength of the current study is that the serum amylase level was consistently measured in all subjects, and those subjects had been treated with either DPP4is or GLP-1 analogs as monotherapy. The incidence of elevated serum pancreatic amylase levels beyond normal range was calculated as 6.12% in the DPP4is group although the frequency was 0% in the GLP-1 analog group. Measurement of serum amylase consistently might have clinical meaning to catch the onset of pancreatitis and minimize the side effects due to DPP4is and GLP-1 analogs.

[Amylase inhibitors from Streptomyces lucensis VKPM Ac-1743 and Streptomyces violaceus VKPM Ac-1734]

Inhibitors synthesized by the Streptomyces lucensis VKPM AS-1743 and Streptomyces violaceus VKPM AS-1734 strains were studied for their influence on amylases of different origin. The effect of the inhibitors was shown to be different on fungal amylase, pancreatic amylase, and amylase from human blood. It has been found that the studied inhibitors are substances of a pseudooligosaccharide nature and exhibit their activity and stability over a wide range of pH and temperature values. The physico-chemical and biochemical properties of isolated inhibitors were compared with those of known microbial inhibitors of α-glucosidases.

Effect of tetracycline on pancreas and liver function of adult male albino rats

The effect of tetracycline, at two doses of 50 and 200 mg kg−1 daily, was studied on pancreatic and liver tissue function for 14 and 21 days in adult male albino rats. For pancreatic function the parameters studied were content of amylase and lipase in pancreas, serum amylase and lipase, serum glucose and faecal fat excretion. For liver function, liver specific enzymes in serum, namely alanine amino transaminase, aspartate amino transaminase and lactate dehydrogenase were estimated. In addition, total lipid, antiperoxidative enzymes and lipid peroxidation were measured in pancreas and liver. The content of amylase and lipase in pancreas showed a small but significant decrease in the rats given 50 mg kg−1 for 21 days and the decrease was much more significant in those receiving the 200 mg kg−1 dose. In pancreas free radical levels show a significant increase and reduced glutathione shows a substantial decrease at the 50 mg kg−1 level and a significant change in these parameters was observed at the 200 mg kg−1 dose. Antioxidant enzymes, superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase, showed a small but significant decrease in the pancreas of the rats treated with 50 mg kg−1 tetracycline. A significant decrease in the antioxidant enzymes level was observed at the 200 mg kg−1 dose. In the liver, free radical levels and reduced glutathione were within the normal range at the 50 mg kg−1 level and significant changes were observed at 200 mg kg−1. The antioxidant status was unaffected in liver after treatment with tetracycline at the 50 mg kg−1 level and a significant decrease was observed at the higher dose. Our results reveal the safe nature of tetracycline with respect to the liver at the lower dose tested, whereas, both the higher and lower doses seem to have detrimental effect on the pancreas as revealed by the rise in free radical levels and decrease in the antioxidant enzyme levels.

Biochemical and histological effects of exendin-4 (exenatide) on the rat pancreas

AIMS/HYPOTHESIS

Exendin-4 is a 39 amino acid agonist of the glucagon-like peptide receptor and has been approved for treatment of type 2 diabetes. Many reports describe an increased incidence of acute pancreatitis in humans treated with exendin-4 (exenatide). Previous studies have evaluated the effect of exendin-4 on beta cells and beta cell function. We evaluated the histological and biochemical effects of exendin-4 on the pancreas in rats.

METHODS

We studied 20 Sprague-Dawley male rats, ten of which were treated with exendin-4 and ten of which were used as controls. The study period was 75 days. Serum and pancreatic tissue were removed for biochemical and histological study. Blood glucose, amylase, lipase, insulin and adipocytokines were compared between the two groups.

RESULTS

Animals treated with exendin-4 had more pancreatic acinar inflammation, more pyknotic nuclei and weighed significantly less than control rats. They also had higher serum lipase than control animals. Exendin-4 treatment was associated with lower insulin and leptin levels as well as lower HOMA values than in the untreated control group.

CONCLUSIONS/INTERPRETATION

Although the use of exendin-4 in rats is associated with decreased weight gain, lower insulin resistance and lower leptin levels than in control animals, extended use of exendin-4 in rats leads to pancreatic acinar inflammation and pyknosis. This raises important concerns about the likelihood of inducing acute pancreatitis in humans receiving incretin mimetic therapy.

Lead toxicity in alfalfa plants exposed to phytohormones and ethylenediaminetetraacetic acid monitored by peroxidase, catalase, and amylase activities

This manuscript describes the toxicity of lead in alfalfa plants treated with ethylenediaminetetraacetic acid (EDTA) and the phytohormones indole-3-acetic-acid (IAA), gibberellic acid (GA), and kinetin (KN), on catalase (CAT), ascorbate peroxidase (APOX), and total amylase activity (TAA). In all cases Pb was used at 40 mg/L; EDTA at 0.2 mM (equimolar to Pb); and IAA, GA, and KN at 1, 10, and 100 microM, respectively. An experiment containing Pb at 40 mg/L, 0.2 mM EDTA, and IAA and KN at 100 microM each was performed to determine changes in TAA. A control (plain nutrient solution) also was used for comparison. In all cases the treatments were performed in triplicate. Standard procedures were followed to determine the activity of the respective enzymes. After 10 d of exposure to the treatments, the leaves were harvested, homogenized, and centrifuged, and the supernatants were analyzed for CAT, APOX, and TAA. All determinations were performed in triplicate. The results demonstrated that CAT was reduced significantly (p < 0.05) by all treatments containing Pb, IAA, and GA at 10 and 100 microM. However, only the treatments Pb/EDTA/KN at 1, 10, and 100 microM reduced the APOX. The TAA in leaves of alfalfa plants was increased significantly (p < 0.05) by all treatments. Overall, the results suggest that the CAT tests showed no lead toxicity to the alfalfa seedlings. However IAA at 10 and 100 muM revealed toxicity to the CAT enzyme. In addition, the APOX tests exhibited no toxicity to the peroxidase enzyme with the exception of Pb/EDTA/KN treatments. Finally, the TAA tests showed high Pb/EDTA/phytohormone toxicity to the amylase enzyme in alfalfa seedlings.

C-type natriuretic peptide enhances amylase release through NPR-C receptors in the exocrine pancreas

Several studies show that C-type natriuretic peptide (CNP) has a modulatory role in the digestive system. CNP administration reduces both jejunal fluid and bile secretion in the rat. In the present study we evaluated the effect of CNP on amylase release in isolated pancreatic acini as well as the receptors and intracellular pathways involved. Results showed that all natriuretic peptide receptors were expressed not only in the whole pancreas but also in isolated pancreatic acini. CNP stimulated amylase secretion with a concentration-dependent biphasic response; maximum release was observed at 1 pM CNP, whereas higher concentrations gradually attenuated it. The response was mimicked by a selective natriuretic peptide receptor (NPR-C) agonist and inhibited by pertussis toxin, strongly supporting NPR-C receptor activation. CNP-evoked amylase release was abolished by U-73122 (PLC inhibitor) and 2-aminoethoxydiphenyl borate (2-APB) [an inositol 1,4,5-triphosphate (IP(3)) receptor antagonist], partially inhibited by GF-109203X (PKC inhibitor), and unaltered by ryanodine or protein kinase A (PKA) and protein kinase G (PKG) inhibitors. Phosphoinositide hydrolysis was enhanced by CNP at all concentrations and abolished by U-73122. At 1 and 10 pM, CNP did not affect cAMP or guanosine 3',5'-cyclic monophosphate (cGMP) levels, but at higher concentrations it increased cGMP and diminished cAMP content. Present findings show that CNP stimulated amylase release through the activation of NPR-C receptors coupled to the PLC pathway and downstream effectors involved in exocytosis. The attenuation of amylase release was likely related to cAMP reduction. The augmentation in cGMP supports activation of NPR-A/NPR-B receptors probably involved in calcium influx. Present findings give evidence that CNP is a potential direct regulator of pancreatic function.

Comparative effects of different triazole compounds on growth, photosynthetic pigments and carbohydrate metabolism of Solenostemon rotundifolius

The effects of two triazole compounds, triadimefon and hexaconazole, on the growth and carbohydrate metabolism were studied in Solenostemon rotundifolius Poir., Morton plants under pot culture. Plants were treated with triadimefon at 15mg l(-1) and hexaconazole at 10mg l(-1) separately by soil drenching on 80, 110 and 140 days after planting (DAP). The plants were harvested randomly and growth parameters were studied on 90, 120 and 150 DAP for determining the effect of both the triazole on growth and chlorophyll pigments. These triazole compounds increased the chlorophyll pigments. However, both the treatments decreased the fresh and dry weights of shoot and leaf area. Both these triazole resulted in a marginal increase in starch content and decreased the sugar contents. The carbohydrate metabolizing enzymes alpha- and beta-amylase activities were reduced and invertase activity increased in S. rotundifolius under triadimefon and hexaconazole treatments.

Use of X-ray absorption spectroscopy and biochemical techniques to characterize arsenic uptake and reduction in pea (Pisum sativum) plants

Arsenite (As(III)) and arsenate (As(V)) uptake by peas was investigated using inductively coupled plasma/optical emission spectroscopy (ICP-OES) at pH below 4 and at pH 5.8. Additionally, total amylolitic activity and alpha-amylase (1,4-alpha-d-glucan glucanohydrolase; EC 3.2.1.1) activity was assayed in plants exposed to arsenic treatments. At pH below 4, the uptake for As(III) and As(V) in roots was 137 and 124 mg As kg(-1) dry weight (d wt), respectively. Translocation of arsenic to the aerial part was relatively low ( approximately 5mg As kg(-1) d wt). The uptake for As(III) and As(V) in roots at pH 5.8 was about 43 and 30 mg As kg(-1) d wt, respectively, and translocation of As to the aerial part was not detectable. None of the arsenic treatments affected the total amylolitic activity in roots; however, the shoots from all treatments showed an increase in the total amylolitic activity. Alpha-amylase activity in the pea leaves was not significantly affected by arsenic treatments. X-ray absorption spectroscopy (XAS) studies showed a reduction of As(V) to As(III) in the roots. From linear combination X-ray absorption near edge structure (LC-XANES) fittings, it was determined that arsenic was present as a mixture of As(III) oxide and sulfide in pea roots.

Effect of Insulin on Acetylcholine-Evoked Amylase Release and Calcium Mobilization in Streptozotocin-Induced Diabetic Rat Pancreatic Acinar Cells

This article investigated the effect of acetylcholine (ACh) on amylase secretion and cellular calcium homeostasis [Ca2+]i in streptozotocin (STZ; 60 mg kg(-1), intraperitoneally)-induced diabetic rats compared to age-matched controls in an attempt to understand the cellular mechanism of exocrine pancreatic insufficiency. ACh-evoked marked dose-dependent increases in amylase release from isolated pancreatic acini and acinar cells in healthy control rats. In diabetic acini and acinar cells, the ACh-evoked amylase release was significantly (P < 0.05) reduced compared to healthy acini and acinar cells. Insulin (10(-6)M) stimulated amylase release in both control and diabetic acini and acinar cells but with a much reduced effect in diabetic tissues. Combining insulin with ACh had no significant effect on amylase release compared to the effect of ACh alone. In fura-2 loaded pancreatic acinar cells of normal rats, ACh (10(-5)M) evoked a large initial rise (peak) in [Ca2+]i followed by a decline into a plateau phase. This effect of ACh was significantly (P < 0.05) reduced in fura-2 loaded diabetic acinar cells. In control cells, insulin had no significant effect on either basal or ACh evoked [Ca2+]i compared to the effect of ACh alone. In contrast, in diabetic acinar cells, insulin significantly (P < 0.05) attenuated the effect of ACh. In a normally free extracellular Ca2+ medium [Ca2+]o containing 1 mM EGTA, the ACh-evoked [Ca2+]i in normal healthy fura-2 loaded acini was similar to the response obtained with ACh in fura-2 loaded diabetic acini. Together, the results indicated that exocrine pancreatic insufficiency is associated with decreased [Ca2+]i due to less Ca2+ released from internal stores and less Ca2+ entering the cell from the extracellular medium.

Does potentized HgCl2 (Mercurius corrosivus) affect the activity of diastase and alpha-amylase?

BACKGROUND

Homeopathic drugs even with dilutions beyond 10(23) (high potencies) are frequently used, although their working mechanism is still unknown. Curative information preserved in solvent structure is postulated to exert biologic effects.

OBJECTIVE

The objective was to test for a stimulating or inhibiting effect of high potencies of the homeopathic remedy HgCl2 (Mercurius corrosivus) on two sugar hydrolases.

METHODS

High potencies were produced using stepwise dilution plus shaking. Controls included potentized solvent (aqua bidestillata), equimolar dilutions without shaking, and enzyme-free references. Tested were potencies with dilution factors 1:200 (CC) on diastase extract from winter barley, and 1:100 (C) on alpha-amylase from hog pancreas. Enzyme activity was colorimetrically determined by Lugol's iodine-starch reaction.

RESULTS

An inhibiting effect of HgCl2 on enzyme activities was observed only in low potencies and dilutions. Statistically significant differences between potencies and controls were not found in randomized and blinded experiments.

CONCLUSIONS

This experimental design provided independent reproducible results of cell-free in vitro assays. However, it did not indicate an effect of potentized HgCl2 on hydrolases. Demonstrating potency effects may require additional experimental features.

Frequency of post-ERCP pancreatitis in a single tertiary referral centre without and with routine prophylaxis with gabexate: a 6-year survey and cost-effectiveness analysis

BACKGROUND AND STUDY AIMS

Several drugs have been used for the prevention of post-ERCP pancreatitis with conflicting results and no data referring to the routine use of a pharmacological prophylaxis have been published up to now. Aim of the study was to evaluate the frequency of post-ERCP pancreatitis and costs in a series of consecutive patients who have undergone ERCP procedures before and after the introduction of a routine prophylaxis with gabexate in all cases.

PATIENTS AND METHODS

Data from 1312 patients who underwent ERCP procedures without gabexate prophylaxis and from 1149 consecutive patients with 1g i.v. gabexate, were retrospectively evaluated during a 6-year period. Patients were also subdivided in standard- and high-risk subjects, on the basis of patient- and technique-related risk factors: 984 subjects (39.9%) had one or more conditions that placed them at high risk for post-ERCP pancreatitis.

RESULTS

Post-ERCP pancreatitis was reported in 76 out of 2461 patients (3.1%). The frequency of pancreatitis appeared significantly reduced in the gabexate period in comparison with before gabexate in overall cases (2.2% versus 3.9%; p=0.019); however, the reduction was significant only for high-risk patients (3.8% versus 7.3%; p=0.001). Severe hyperamylasaemia at 4-6h and 24h after the procedure was also significantly reduced only in high-risk patients (p=0.001). Routine prophylaxis with gabexate appeared cost-effective in high-risk patients.

CONCLUSIONS

Routine gabexate prophylaxis was associated with a significant reduction of post-ERCP pancreatitis rate, severe hyperamylasaemia and hospitalisation-related costs only in high-risk patients. However, gabexate appeared unable to reduce the incidence of severe pancreatitis.

Selected biochemical parameters and ultrastructural picture of pancreas due to Ulinastatin treatment of experimental acute pancreatitis

Urinary trypsin inhibitor (UTI, Ulinastatin) is a protease inhibitor that has not been yet used in Europe in any experimental trial of severe acute pancreatitis. We have combined the experimental model of severe, hemorrhagic form of acute pancreatitis, and pharmacological treatment with a protease inhibitor. Male Wistar rats were divided into four experimental groups: healthy controls, operated, operated with experimentally induced acute pancreatitis, and animals with acute pancreatitis--treated with UTI preparations. Subjects in the last group were administered UTI intraperitoneally 1 h after pancreatitis induction in an average standard dose of 3000 units/animal. Additionally, four subgroups were created in this treated group, based on the UTI administration time--number of standard doses received: 2 h - 1 standard dose, 6 h - 5 standard doses, 12 h - 11 doses, 24 and 48 h - 15 doses. Statistically significant differences in the serum amylase and lipase activity between the UTI-treated and non-treated subjects were found. In the group of non-treated animals, there a profound destruction of cellular organelles was observed with a total degradation of nuceli, endoplasmatic reticulum and zymogen granules. However, in the UTI-treated subjects, pathological processes proceeded with the significantly slower pace and in much smaller quantities.

Effects of gabexate mesilate (FOY) on amylase and phospholipase A2 in human serum and pancreatic juice

The precise inhibitory action of gabexate mesilate (GM) on the various pancreatic enzymes remains unclear. We designed this study to investigate the enzyme inhibitory action of GM in the serum and directly in the pancreatic juice. We observed 16 cases with postoperative pancreatic drainage. Patients were randomly assigned to one of two groups, to receive GM at a dose of 600 mg/24 hr (treated group: 8 patients) or a physiological solution (control group: 8 patients) by continuous intravenous infusion. In both groups pancreatic juice and serum were sampled three times: before infusion began (T0) and at 12 hr (T1) and 24 hr after infusion ended (T2). At the end of the study, seven patients received octreotide and the volume of pancreatic secretion was determined. No statistical difference was observed in serum amylase and phospholipase A2 activity in the treated and control groups. On the contrary, amylase and phospholipase A2 activity in the pancreatic juice diminished significantly only in the treated group, and in these patients a GM metabolite was also detectable in the pancreatic secretion. The volume of pancreatic secretion decreased only after infusion of octreotide. The enzyme inhibition in the pancreatic gland itself and the central role of inhibition of phospholipase A2 in the enzyme cascade responsible for activating other proteases, confirm the therapeutic use of GM in acute pancreatitis. An association of GM and octreotide during acute pancreatitis should be useful because of their different mechanisms.

Dietary virgin olive oil enhances secretagogue-evoked calcium signaling in rat pancreatic acinar cells

OBJECTIVE

We evaluated the long-term effects of a fat-enriched diet (virgin olive oil) on calcium mobilization and amylase secretion induced by cholecystokinin-octapeptide (CCK-8) in rat pancreatic acinar cells. Olive oil is a major component of the Mediterranean diet, and its role in human health is actively being debated.

METHODS

Weaning male Wistar rats (21 d old) were assigned to one of two experimental groups and fed for 8 wk with a commercial chow (control group) or an experimental diet (olive group) containing 100 g/kg of virgin olive oil as dietary fat. Intracellular free calcium [Ca(2+)](i) levels were determined by loading the pancreatic cells with the fluorescent ratio-metric calcium indicator Fura-2 on an inverted fluorescent microscope. For measurement of amylase secretion, cells were incubated with the appropriate secretagogue for 30 min, and amylase activities in the supernatant were determined by the Phadebas blue starch method. Analysis of variance was used to test differences between groups.

RESULTS

Compared with the control group, the CCK-8-induced increase in [Ca(2+)](i) occurred in cells from rats in the olive group (P < 0.05). This stimulatory effect of dietary virgin olive oil was observed in calcium oscillations and large [Ca(2+)](i) transients induced by low (20 pM/L) and high (10 nM/L) concentrations of CCK-8, respectively. In addition to the effects of dietary virgin olive oil on calcium mobilization, it increased (P < 0.05) amylase secretion in response to CCK-8. Olive oil treatment did not significantly alter resting [Ca(2+)](i) or amylase release values compared with the control group. Similar results were obtained when pancreatic acinar cells were stimulated with a high concentration of acetylcholine (10 microM/L).

CONCLUSION

The present results demonstrate that a diet supplemented with virgin olive oil can modify pancreatic cell function as assessed by [Ca(2+)](i) mobilization and amylase release evoked by secretagogues in rat pancreatic acinar cells. A role for fatty acids in calcium signaling is suggested.

The Influence of a load of L-arginine on serum amino acids and pancreatic apoptosis/proliferation and ATP levels in the rat

OBJECTIVES

Administration of high doses of amino acids like ethionine, methionine, and arginine causes pancreatic tissue damage. The initial mechanism behind these effects is not known. The aim of this study was to show the early effects of a load of L-arginine on programed cell death/proliferation and ATP levels in the pancreas.

METHODS

We analyzed in rats the effects of intraperitoneal administration of L-arginine on serum amino acids, pancreatic cell apoptosis/proliferation, and ATP levels at 8, 16, and 24 hours. Serum amino acid concentrations were measured with HPLC, tissue ATP was measured fluorometrically, apoptosis was studied with caspase-3 activity and histone-associated DNA-fragments, and proliferation was studied with thymidine autoradiography.

RESULTS

After a load of l-arginine, there were initially increased serum levels of L-arginine and L-citrulline, but these fell below control levels after 24 hours as well as amino acids in the glutamate family (ornithine, proline, histidine, and glutamine). Initially, increased ATP levels in the pancreatic tissue returned to control levels at 24 hours. The acinar cells proliferation was suppressed and the apoptosis rate strongly increased at 16 and 24 hours. Pancreatic histology showed vacuole formation in the acinar cells at 8 hours. At 16 hours, there was less vacuolization, but apoptotic bodies were seen, and at 24 hours there was cell degeneration but no necrosis.

CONCLUSIONS

After a load of l-arginine, amino acid metabolism causes a high ATP production in the pancreatic tissue that may cause mitochondrial initiation of cell death.

Sex-related differences in effect of ethanol administration and folic acid supplementation on pancreatic amylase in rats

The present study was designed to determine whether folic acid supplement is sufficient to reverse the negative effects of ethanol consumption on amylase activity during gestation, lactation, and growth. Moreover, this study investigated the sex-related differences in amylase content in the pancreatic tissue, serum, and urine. The animals were randomized into three groups: Control group (CG) received water and a basic rat diet during pregnancy, lactation, and growth; Ethanol-rats (EG) were fed an ethanol diet during pregnancy, the suckling period, and growth until death; and Ethanol + folic acid group (E + FG) were handled the same way as those of EG, except they received a folic acid supplement from reproduction until the end of experimental period. Our results showed that ethanol consumption decreased the pancreatic amylase level in offspring rats at 2 months postpartum. Folic acid supplementation did not alter pancreatic amylase activities. In offspring males, ethanol administration decreased serum amylase activity at 2 months postpartum. Folic acid supplementation in males resulted in higher serum amylase levels than those corresponding to the ethanol-fed group. In females, no significant differences between groups in serum amylase levels were found. Ethanol consumption decreased urinary amylase excretion (at 30 days and 2 months postpartum), but the folic acid-supplemented group showed a more pronounced decrease in urine amylase activity than in the ethanol-fed group. At 30 days postpartum, no sex difference in urinary amylase was identified. However, in general, males showed higher values for urine amylase than females at 2 months postpartum. A folic acid-supplemented diet exerts an advantageous effect on amylase in serum in offspring males at 2 months postpartum of mothers fed ethanol during gestation and lactation periods, because amylase renal absorption is increased. In offspring females, amylase renal absorption is also increased, but we did not observed an advantageous effect on amylase in serum. It may be that sexual differentiation in females at 2 months postpartum exerts a definitive effect on amylase in serum. We found a sex-related difference in amylase activities; therefore, we suggest that in future all results of the exocrine pancreas function, in male and female animals, be analyzed separately.

Melatonin and its precursor, L-tryptophan: influence on pancreatic amylase secretion in vivo and in vitro

Melatonin, considered as a main pineal product, may be also synthetized in the gastrointestinal tract from L-tryptophan. Melatonin has been recently shown to affect insulin release and its receptors have been characterized in the pancreas however, the effects of melatonin on the pancreatic enzyme secretion have not been examined. The aim of this study was to investigate the effects of melatonin or L-tryptophan on amylase secretion in vivo in anaesthetized rats with pancreato-biliary fistulas, and in vitro using isolated pancreatic acini. Melatonin (1, 5 or 25 mg/kg) or L-tryptophan (10, 50 or 250 mg/kg) given to the rats as a intraperitoneal (i.p.) bolus injection produced significant and dose-dependent increases in pancreatic amylase secretion under basal conditions or following stimulation of enzyme secretion by diversion of bile-pancreatic juice. This was accompanied by a dose-dependent rise in melatonin plasma level. Stimulation of pancreatic enzyme secretion caused by melatonin or L-tryptophan was completely abolished by vagotomy, deactivation of sensory nerves with capsaicin or pretreatment with CCK1 receptor antagonists (tarazepide or L-364,718). Pretreatment with luzindole, an antagonist of melatonin MT(2) receptor failed to affect melatonin- or L-tryptophan-induced amylase secretion. Administration of melatonin (1, 5 or 25 mg/kg i.p.) or L-tryptophan (10, 50 or 250 mg/kg i.p.) to the rats resulted in the dose-dependent increase of cholecystokinin (CCK) plasma immunoreactivity. Enzyme secretion from isolated pancreatic acini was not significantly affected by melatonin or L-tryptophan used at doses of 10(-8) -10(-5) M. We conclude that exogenous melatonin, as well as that produced endogenously from L-tryptophan, stimulates pancreatic enzyme secretion in vivo while increasing CCK release. Stimulatory effect of melatonin or L-tryptophan on the exocrine pancreas involves vagal sensory nerves and the CCK release by these substances.

Modulation by thyroid hormones of rat parotid amylase secretion stimulated by 5-hydroxytryptamine

The effects of 5-hydroxytryptamine (5-HT) upon amylase secretion by rat parotid glands were studied in three groups of animals: (a) intact control rats (euthyroid rats); (b) hypothyroid rats obtained by surgical thyroidectomy 2 wk before the experiments; and (c) hyperthyroid rats obtained by the administration of sodium l-triiodothyronine for 2 wk before the experiments. Hyperthyroid rats showed significantly higher baseline amylase release than control rats. When the glands were stimulated with 5-HT (30 micro m), amylase release was significantly lower in the hypothyroid group and higher in the hyperthyroid rats than in control group. Addition of cholinergic, adrenergic or substance P antagonists did not modify 5-HT-stimulated amylase activity. The effects of 5-HT were partly but significantly blocked by the addition of 10 micro m methysergide (HT1/2/7 receptor blocker) in the three groups of rats. In contrast, 10 micro m ketanserine (HT2A receptor blocker) partly blocked the response to 5-HT only in the hyperthyroid animals. It was concluded that 5-HT induces amylase secretion by rat parotid glands through specific serotoninergic receptors, and that thyroid status modulates the 5-HT effect.

Evidence that nitric oxide does not directly contribute to methacholine-induced amylase secretion in rabbit parotid acinar cells

Nitric oxide (NO) is a short-lived free radical and is a widespread intra- and intercellular messenger molecule involved in various physiological functions. We have demonstrated previously that the muscarinic agonist methacholine induces endogenous generation of NO in rabbit parotid acinar cells. Since methacholine also simultaneously evokes amylase secretion, we investigated the effect of NO on the methacholine-induced exocytotic amylase secretion in rabbit parotid acinar cells. Methacholine-evoked amylase secretion was clearly reduced in the absence of extracellular Ca(2+). The Ca(2+)-mobilizing reagents A23187 and thapsigargin, which stimulate NO generation, also evoked amylase secretion. This response seemed to be caused by NO generated by the activation of endogenous Ca(2+)-regulated NO synthase. However, N(G)-nitro-L-arginine methyl ester (L-NAME), a specific NOS inhibitor, and the NO scavenger haemoglobin had no effect on methacholine-induced amylase secretion. The NO generator sodium nitroprusside (SNP) failed to evoke amylase release. We further studied the effects of L-NAME and SNP on methacholine-induced amylase secretion in crudely dispersed parotid gland cell clusters containing nerve tissue. In this preparation, L-NAME inhibited methacholine-induced amylase secretion and SNP evoked amylase secretion. It is thus unlikely that NO contributes directly to methacholine-induced amylase secretion in rabbit parotid acinar cells. NO appears rather to affect to nerve tissues in the cell suspension.

The aqueous extract of Triumfetta semitriloba (Tiliaceae) does not inhibit the in-vitro hydrolytic activity of the major pancreatic enzymes

The aqueous extract of Triumfetta semitriloba is part of the Costa Rican folk pharmacopoeia. It shows no in-vitro inhibitory action on the hydrolytic activity of porcine pancreatic amylase, lipase or proteases, thus diminishing the concern of intestinal malabsorption in human beings.

The anti-inflammatory effect of methylprednisolone occurs down-stream of nuclear factor-kappaB DNA binding in acute pancreatitis

Glucocorticoids are potent anti-inflammatory drugs. The molecular mechanisms underlying these effects have not yet been fully revealed. The aim of the present study was to establish whether methylprednisolone pretreatment is beneficial and if it can block the pancreatic DNA binding of the transcription factor nuclear factor-kappaB (NF-kappaB) and proinflammatory cytokine synthesis during cholecystokinin-octapeptide (CCK)-induced acute pancreatitis in rats. Additionally, we set out to investigate the potential effects of methylprednisolone and CCK on pancreatic heat shock protein (HSP) synthesis. The dose-response (5-40 mg/kg) and time-course (6-72 h) curves of methylprednisolone on pancreatic HSP60 and HSP72 synthesis were evaluated following methylprednisolone treatment. We demonstrated that methylprednisolone specifically and dose-dependently induced HSP72 in the pancreas of rats, while it did not have a significant effect on HSP60 expression. The pancreatitis was induced near the peak level of HSP72 synthesis (2 x 30 mg/kg body weight [b.w.] methylprednisolone i.m. at an interval of 12 h, followed by a 12-h recovery period after the second injection of methylprednisolone) by administering 2 x 100 microg/kg CCK subcutaneously at an interval of 1 h. The injections of CCK in the vehicle-pretreated group significantly elevated the levels of pancreatic HSP60 and HSP72 2-4 h after the second CCK injection. Methylprednisolone pretreatment ameliorated many of the examined laboratory (the pancreatic weight/body weight [p.w./b.w.] ratio, the serum amylase activity, the plasma trypsinogen activation peptide concentration, the pancreatic levels of tumor necrosis factor-alpha and interleukin-6, the degree of lipid peroxidation, protein oxidation, nonprotein sulfhydryl group content and the pancreatic myeloperoxidase activity) and morphological parameters of the disease. Methylprednisolone pretreatment did not influence pancreatic NF-kappaB DNA binding, but decreased proinflammatory cytokine synthesis in this acute pancreatitis model. The findings suggest that the anti-inflammatory effect of large doses of methylprednisolone in secretagogue-induced pancreatitis occurs downstream of NF-kappaB DNA binding, and that increased pancreatic HSP72 synthesis may play a role in the protective effect of the drug.

Mechanisms of Chinese herb emodin and somatostatin analogs on pancreatic regeneration in acute pancreatitis in rats

INTRODUCTION

Studies have revealed that emodin is a potent agent in the management of clinical and experimental acute pancreatitis, but the molecular mechanisms by which emodin produces its biologic effects, especially on pancreatic regeneration after acute pancreatitis, remain unknown. Numerous experimental and clinical studies have shown that somatostatin analogs have favorable effects on acute pancreatitis, but their role in the management of acute pancreatitis remains controversial.

AIM

To investigate mechanisms of the Chinese herb emodin and somatostatin analogs (SSa; Sandostatin) in acute pancreatitis of rats by analyzing the changes in pancreatic tissue cytokine transforming growth factor beta1 (TGFbeta1) and epidermal growth factor (EGF) gene expression, DNA synthesis, total protein content, and the relations between them.

METHODOLOGY

Acute pancreatitis was induced by intraperitoneal infusion of cerulein in rats. Emodin was administered intravenously and Sandostatin was administered subcutaneously at the time of induction of pancreatitis and 24, 48, and 72 hours afterward. Rats were killed at 6, 24, 48, 72, and 96 hours after the operation. The mRNA expression of TGFbeta1 and EGF were evaluated by reverse transcription polymerase chain reaction, and pancreatic tissue DNA synthesis was measured by the 3H-thymidine incorporation method in vitro. Total protein content was detected by Lowry's method.

RESULTS

The serum amylase level was decreased significantly in the emodin-treated and Sandostatin-treated groups in comparison with the nontreated group. Pancreatic tissue DNA synthesis was significantly decreased at 72 hours after the induction of pancreatitis, and a marked increase was observed at 96 hours after treatment with emodin and Sandostatin. Within 48 hours of the induction of pancreatitis, the total protein content in pancreatic tissue declined, but there was a remarkable increase in the emodin-treated group at 96 hours and Sandostatin-treated group at 48 hours. Expression of TGFbeta1 mRNA and EGF mRNA were undetectable in normal pancreas and the nontreated group at 6 hours but was observed from 24 hours to 96 hours after the induction of pancreatitis and reached its maximum at 72 hours. TGFbeta1 mRNA could be detected 6 hours after treatment with emodin and Sandostatin, and its expression was significantly higher in the emodin-treated and Sandostatin-treated groups than in the nontreated group at 24 and 48 hours. The expression of EGF mRNA was significantly higher in the emodin-treated and Sandostatin-treated group than in the nontreated group at 48 hours.

CONCLUSION

It was concluded that mechanisms of the Chinese herb emodin and somatostatin analogs in the management of acute pancreatitis in rats might be ascribed to the upregulation of TGFbeta1 and EGF gene expression, which subsequently increases DNA synthesis and protein content and thus accelerates pancreatic repair and regeneration.

Amylase secretion from dispersed human pancreatic acini: neither cholecystokinin a nor cholecystokinin B receptors mediate amylase secretion in vitro

INTRODUCTION

In humans, cholecystokinin (CCK) stimulates pancreatic secretion, and CCK-A receptor antagonists prevent it in vivo. However, the human pancreas has been reported to express mainly CCK-B receptors.

AIM

To elucidate this discrepancy.

METHODOLOGY

We prepared dispersed acini from human pancreas and examined whether various doses of CCK stimulated the release of amylase, in comparison with the effects of neuromedin C, carbamylcholine, and secretin.

RESULTS

Human pancreatic acini did not respond to any dose of CCK or secretin. Amylase release was stimulated by carbamylcholine and neuromedin C dose-dependently and was inhibited by respective antagonists. The localizations of CCK receptors in the human duodenum were determined. High concentrations of CCK-A receptors were detected in the mucosa as well as in smooth muscle of the duodenum by microautoradiography.

CONCLUSION

In conclusion, human pancreatic acinar cells are responsible for carbamylcholine and neuromedin C but not for secretin. Neither CCK-A nor CCK-B receptor mediates amylase release from human pancreatic acini in vitro. Pancreatic secretion in humans in vivo may be regulated indirectly by CCK (via CCK-A receptors).

Blockade of bradykinin B(2) receptor suppresses acute pancreatitis induced by obstruction of the pancreaticobiliary duct in rats

1. The involvement of bradykinin (BK) B(2) receptor in acute pancreatitis induced by pancreaticobiliary duct ligation was investigated in rats. 2. The activities of amylase and lipase in the serum, the water content of the pancreas, and vacuolization of the acinar cells were significantly increased 2 h after obstruction of the duct in Sprague-Dawley rats. 3. Elevated serum amylase activity, increased pancreatic oedema, and damage of the pancreatic tissue were significantly less marked in plasma kininogen-deficient, B/N-Katholiek rats than in the normal strain, B/N-Kitasato rats 2 h after the ligation. 4. Obstruction of the pancreaticobiliary duct augmented the level of (1-5)-BK (Arg(1)-Pro(2)-Pro(3)-Gly(4)-Phe(5)), a stable BK metabolite, in the blood from 73.0+/-21.7 pg ml(-1) at 0 h to 149.8+/-38.0 pg ml(-1) at 2 h after the induction of pancreatitis in SD rats. 5. Administration of a BK B(2) receptor antagonist, FR173657 (100 mg kg(-1), p.o.) or Hoe140 (100 nmol kg(-1), s.c.), reduced the elevation of amylase and lipase activities in the serum and of pancreatic water content in a dose-dependent manner. The effective attenuation of oedema formation and vacuolization by the antagonists was also confirmed light-microscopically. In contrast, treatment with gabexate mesilate or indomethacin did not cause significant suppression of the pancreatitis. 6. These findings suggest a possible involvement of kinin B(2) receptor in the present pancreatitis model. Furthermore, they point to the potential usefulness of the B(2) receptor in clinical acute pancreatitis.

Effects of dopexamine on acute necrotising pancreatitis in rats

OBJECTIVE

To examine the effects of dopexamine on pancreatic tissue oxygen tension (PtO2) and the extent of acinar injury in rats with acute necrotising pancreatitis

DESIGN

Laboratory study.

SETTING

Medical school, Turkey.

ANIMALS

68 Sprague Dawley rats.

MAIN OUTCOME MEASURES

Cardiorespiratory measurements, pancreatic PtO2, effects on activity of serum amylase and concentration trypsinogen activation peptide (TAP). and histological picture.

RESULTS

The four study groups (sham + saline, sham + dopexamine, acute pancreatitis and acute pancreatitis + dopexamine) were each divided into two; in 9 rats in each, pancreatic biochemistry was studied, and in the remaining 8 in each group serum biochemistry and histology were studied. The groups were comparable with regard to mean arterial pressure, heart rate, arterial blood gases, packed cell volume, and serum amylase activity. The use of dopexamine increased pancreatic PtO2 in the sham + dopexamine group without the important blood pressure changes. The induction of pancreatitis resulted in a significant reduction in pancreatic PtO2 in the pancreatitis groups. The use of dopexamine did not increase pancreatic PtO2. There were no significant differences in plasma TAP concentration and the extent of acinar cell injury in the animals in the pancreatitis groups.

CONCLUSION

Treatment with dopexamine does not improve the pancreatic microcirculation or reduce the extent of acinar cell injury in acute necrotising pancreatitis and is therefore unlikely to be of benefit in patients with pancreatitis.

Cadmium inhibits stimulated amylase secretion from isolated pancreatic lobules of the guinea-pig

The effect of cadmium chloride on pancreatic exocrine secretion 'in vitro' was examined using guinea-pig isolated lobules. Cadmium (10(-3)M) stimulated amylase release when added alone to the incubation medium and the increase of amylase was unaffected by atropine. Cadmium (10(-4)M) did not significantly modify the basal amylase release. Depolarization of pancreatic nerves with potassium stimulated amylase secretion; the stimulant effect of KCl was completely inhibited by atropine. Cadmium (10(-4)M) inhibited, but did not abolish, the stimulant effect of KCl, indicating a direct effect of the metal on the acinar cell. Cadmium (10(-4)M) also inhibited the amylase release evoked by the secretagogues carbachol and caerulein, which are known to act directly on the acinar cell. Taken together with previous data reporting a large increase of pancreatic cadmium concentration following cadmium ingestion, the strong inhibition of pancreatic secretion observed in our experiments suggests that the exocrine pancreas may be regarded as a possible target organ of cadmium toxicity.

Effect of garlic oil on the levels of various enzymes in the serum and tissue of streptozotocin diabetic rats

Levels of red cell, serum acid, and alkaline phosphatases, serum amylase, alanine and aspartate transferase and bilirubin were examined in streptozotocin-induced diabetic rats treated with garlic oil and compared with the corresponding levels in diabetic control rats, normal rats and normal rats on garlic oil. Values of tissue amylase and total protein were also assessed from the pancreas, liver, and kidney. Treatment of diabetic rats with garlic oil significantly decreased the red cell phosphatase (p < 0.01), serum acid and alkaline phosphatase (p<0.001) when compared to diabetic control rats. Serum alanine and asparate transferases were significantly (p<0.001) decreased as well as serum amylase (p<0.002) in garlic oil treated diabetic rats as compared with diabetic control rats. When treated with garlic oil, however, diabetic and normal rats showed significant increase (p <0.05) in the amylase levels of the pancrease, liver, and kidney.

The influence of sensory nerves and CGRP on the pancreatic regeneration after repeated episodes of acute pancreatitis in rats

Stimulation of capsaicin sensitive nerves or administration of calcitonin gene-related peptide (CGRP) before induction of acute pancreatitis (AP) attenuates pancreatic damage, whereas CGRP administration after development of AP aggravates lesion of pancreatic tissue. The aim of this study was to determine the effect of prolonged activity of sensory nerves or CGRP administration on the pancreatic repair after repeated episodes of AP. Five episodes of acute caerulein-induced pancreatitis (10 microg/kg/h for 5 h s.c.) were performed at weekly intervals in rats receiving either vehicle or capsaicin at the sensory nerve stimulatory dose (0.5 mg/kg, 3 times daily), or CGRP (10 microg/kg, 3 times daily). Two weeks after the last induction of AP morphological signs of pancreatic damage, pancreatic blood flow (PBF), serum and pancreatic amylase activity, fecal chymotrypsin activity, pancreatic weight, pancreatic RNA and DNA content, as well as, serum interleukin-1beta (Il-1beta ) were assessed. Pancreata of animals receiving vehicle alone showed almost full recovery within two weeks after last episode of pancreatitis induction. In capsaicin-treated group of rats, we observed the increase in PBF by 44% and in serum Il-1beta concentration by 91%. The pancreatic amylase activity, fecal activity of chymotrypsin, pancreatic nucleic acids content and DNA synthesis were decreased. In rats treated with CGRP the alterations in PBF, serum Il-1beta concentration, as well as, in pancreatic and fecal activity of enzymes were similar to capsaicin treated group but less pronounced. We conclude that prolonged activity of capsaicin-sensitive sensory nerves and the presence of their main mediator-CGRP during pancreatic regeneration after AP leads to pancreatic functional insufficiency typical for chronic pancreatitis.

A synthetic glycine-extended bombesin analogue interacts with the GRP/bombesin receptor

alpha-amidation of a peptide (which takes place from a glycine-extended precursor) is required to produce biologically active amidated hormones, such as gastrin-releasing peptide (GRP)/Pyr-Gln-Arg-Leu-Gly-Asn-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH(2) (bombesin). It was shown that glycine-extended gastrin mediates mitogenic effects on various cell lines by interacting with a specific receptor, different from the classical CCK(1) or CCK(2) receptors. On the basis of this observation, we have extended the concept of obtaining active glycine-extended forms of others amidated peptides to produce new active analogues. In this study, we have tested the biological behaviour of a synthetic analogue of the glycine-extended bombesin (para-hydroxy-phenyl-propionyl-Gln-Trp-Ala-Val-Gly-His-Leu-Met-Gly-OH or JMV-1458) on various in vitro models. We showed that compound JMV-1458 was able to inhibit specific (3-[125I]iodotyrosyl(15)) GRP ([125I]GRP) binding in rat pancreatic acini and in Swiss 3T3 cells with K(i) values of approximately 10(-8) M. In isolated rat pancreatic acini, we found that JMV-1458 induced inositol phosphates production and amylase secretion in a dose-dependent manner. In Swiss 3T3 cells, the glycine-extended bombesin analogue dose-dependently produced [3H]thymidine incorporation. By using potent GRP/bombesin receptor antagonists, we showed that this synthetic glycine-extended bombesin analogue induces its biological activities via the classical GRP/bombesin receptor.

Epidermal growth factor accelerates pancreatic recovery after caerulein-induced pancreatitis

We examined the influence of endogenous and exogenous epidermal growth factor (EGF) on pancreatic repair after acute pancreatitis. Caerulein-induced pancreatitis was evoked in rats with intact or removed salivary glands and EGF (10 microg/kg) was administered starting 24 h after cessation of caerulein infusion. The dose of EGF 10 microg/kg was chosen because it was the most effective in preliminary experiments when 1, 10 or 50 microg/kg of EGF was used. Caerulein administration caused acute edematous pancreatitis with biochemical and histological manifestation of pancreatic damage, followed by spontaneous regeneration. The effect of salivectomy on the course of acute pancreatitis was slight, resulting in additional reduction in pancreatic blood flow, DNA synthesis and in an increase in plasma interleukin 1beta level. Treatment with EGF accelerated the healing of pancreatic damage, causing an increase in pancreatic blood flow and DNA synthesis. EGF caused faster normalization of plasma amylase and lipase activity and plasma interleukin 1beta concentration, as well as, this peptide accelerated the restoration of pancreatic amylase activity. On histological examination, EGF caused reduction of pancreatic damage and acceleration of tissue repair. We conclude that EGF reduces the severity of pancreatic damage evoked by caerulein-induced pancreatitis-related pancreatic damage and accelerates tissue repair. The beneficial effects of EGF appear to depend, at least in part, on the improvement of pancreatic blood flow, as well as on an increase of pancreatic cell growth and limitation of the activation cytokine release.

Effect of beta-antagonists on isoprenaline-induced secretion of fluid, amylase and protein by the parotid gland of the red kangaroo, Macropus rufus

Selective and non-selective beta-adrenoceptor antagonists were used to block the increases in fluid, protein and amylase secretion caused by sympathomimetic stimulation of the parotid gland of red kangaroos during intracarotid infusion of isoprenaline. ICI118551 at antagonist/agonist ratios up to 300:1 caused increasing but incomplete blockade of fluid secretion, and protein/amylase release. Atenolol at antagonist/agonist ratios up to 300:1 was only marginally more potent than ICI118551 at blocking the fluid, protein and amylase responses. Propranolol at antagonist/agonist ratios of 30:1 was as effective at blocking fluid and protein secretion as the highest ratios of either atenolol or ICI118551. Simultaneous administration of atenolol (30:1) with ICI118551 (30:1) was not as potent as propranolol (30:1). Thus, the beta-adrenoceptor/s in the acini of the kangaroo parotid gland appear to have antagonist-binding affinities atypical of those found for eutherian tissues. The data are consistent with the gland possessing either a single anomalous beta-adrenoceptor or functional beta(2)-receptors in addition to the beta(1)-receptors which are characteristic of eutherian salivary glands.

Disruption of cholecystokinin (CCK)-B receptor gene did not modify bile or pancreatic secretion or pancreatic growth: a study in CCK-B receptor gene knockout mice

Pancreatic exocrine function and bile secretion were examined in cholecystokinin (CCK)-B receptor gene-targeted mice and compared among different genotypes [i.e., CCK-B receptor gene: (+/+), wild-type; (+/-), heterozygous; and (-/-), homozygous deficient]. The histology and protein concentrations in the pancreas also were examined. Amylase release from the dispersed acini was examined in vitro by using the various doses of CCK-8, carbachol, and secretin. In vivo, the bile and pancreatic juice were collected, and the concentrations of amylase and bile acid were measured in anesthetized mice. The responses to CCK (100 pmol/kg) or acetyl-beta-methylcholine (500 nmol/kg) were examined. In vitro studies showed that the maximal effective concentrations of CCK-8 (10(-l0) M), carbachol (10(-5) M), and secretin (5 x 10(-7) M) were comparable for all genotypes. Fluid, amylase, and bile acid outputs in vivo also were comparable for all genotypes. Pancreatic wet weight and protein concentrations were not significantly different, and no abnormal findings were observed on histologic examination in any genotype. These results indicated that the CCK-B receptor has no role in pancreatic growth, exocrine secretion, or bile secretion in adult mice.

Corticosteroid-induced pancreatitis in patients with autoimmune bullous disease: case report and prospective study

Corticosteroid pulse therapy using very high doses may produce corticosteroid-induced pancreatitis (CIP) that is unexpected during conventional oral corticosteroid therapy and may sometimes be fatal. Our goal was to evaluate the relation between pulse corticosteroid administration and pancreatitis. A case of CIP is reported, and a prospective study was performed. Corticosteroid pulse therapy followed by 30 mg prednisolone orally was utilized in 7 hospitalized patients with autoimmune bullous disease, and serum pancreatic enzymes were measured during therapy. The case report revealed reproducible pancreatitis in a dose-dependent manner after 2 corticosteroid regimens. In the prospective study, serum pancreatic enzyme levels increased significantly within several days after pulse therapy, then decreased with tapering of the dose of oral prednisolone. Laboratory pancreatic alterations appear to be induced within days after pulse corticosteroid administration in a dose-dependent manner: less than 25 mg of oral prednisolone may be below threshold to alter the pancreatic enzyme level.

Oral administration of sepimostat mesilate prevents acute alcohol pancreatic injury in rats

The preventive effect of a novel synthetic serine protease inhibitor, sepimostat mesilate (sepimostat), on acute alcohol pancreatic injury, induced by exocrine hyperstimulation and ethanol administration, was assessed and compared with that of a similar protease inhibitor, camostat mesilate (camostat). Conscious rats were infused with 1 microg mL(-1) h(-1) caerulein intravenously for 6 h and with 0.1 g mL(-1) h(-1) ethanol for 9 h, with the latter infusion beginning 3 h after the start of the caerulein infusion. Sepimostat or camostat was administered orally 1 h before the caerulein infusion. Rats infused with caerulein plus ethanol showed increased plasma amylase and lipase activities, and aggravated pancreatic interstitial oedema when compared with rats given caerulein alone. Sepimostat at 10 and 30 mg kg(-1) prevented the increase in plasma amylase and lipase activities caused by caerulein plus ethanol infusion. Sepimostat at 30 mg kg(-1) suppressed the histological change. Camostat did not show any preventive effects at the equivalent dose. When conscious rats were infused with 1 microg mL(-1) h(-1) caerulein alone intravenously for 6 h, plasma amylase and lipase activities were increased compared with rats given saline. Neither drug prevented the increase in these activities at 30mg kg(-1). Our results suggest that sepimostat has superior preventive effects on alcohol-induced acute pancreatic injury compared with camostat. Sepimostat may thus be a useful drug in the therapy of alcohol-induced pancreatitis.

Sodium stibogluconate (pentostan) overdose in a patient with acquired immunodeficiency syndrome

A 32-year-old man with acquired immunodeficiency syndrome (AIDS) admitted to the hospital for treatment of visceral leishmaniasis was inadvertently given 10 times the prescribed first dose of sodium stibogluconate ([Sb] 6.5 g instead of 0.65 g). He experienced no immediate major toxicity during the first 48 hours, but a significant rise of pancreatic enzyme activities was observed (amylase at 10 times the upper limit of normal, lipase at 50 times the upper limit of normal) without clinical signs or indications on computed tomography (CT) of pancreatitis. The third day after the overdose, he developed appendicitis, which appeared coincidental; he recovered uneventfully from surgery. Most of the overdose of Sb was eliminated within the first few hours. Pharmacokinetics remained linear; the rapid, long elimination half-lives (2.7 hours and 54 hours, respectively) were similar to those in previously published results. The administration of a chelating agent, dimercaptosuccinic acid (DMSA), 72 hours after the Sb overdose did not modify the pharmacokinetics of the medication.

Salivary amylase activity of rats fed a low calcium diet

Wistar strain rats fed low calcium diets (1, 2, 3, 4, 6 and 8 weeks) exhibited changes in secretory function of whole saliva. In particular, there were changes in salivary flow rate, total salivary protein, amylase enzyme activity, salivary amylase content and the level of cyclic AMP in the parotid gland acinar cell. Although there were no changes for the first 3 weeks, the levels increased at week 4 and decreased at week 6. The wet weight of the parotid gland started to decrease at week 4. These results suggest that when fed low calcium diets for long periods of time, rats develop defective salivary secretion.

Inhibitory regulation of amylase release in rat parotid acinar cells by benzodiazepine receptors

This study examined the influence of benzodiazepine receptors on amylase release from rat parotid acinar cells. Diazepam (10(-8)-10(-6) M), which is a potent agonist of both central- and peripheral-type benzodiazepine receptors, dose dependently decreased amylase release induced by isoprenaline and carbachol, which are beta-adrenoceptor and muscarinic receptor agonists, respectively. The maximum inhibitory response was obtained with 10(-6) M diazepam: amylase release was decreased to 57% (isoprenaline) and 39% (carbachol) of maximal levels, while these responses were completely inhibited by propranolol and atropine, respectively. Clonazepam and 7-chloro-1,3-dihydro-1-methyl-5-p-chlorophenyl)-2H-1,4-benzodiazepine-2- one (Ro 5-4864), which are selective agonists of central- and peripheral-type benzodiazepine receptors, respectively, also produced a significant and dose-dependent decrease in isoprenaline-induced amylase release. The inhibitory potency was diazepam > clonazepam > Ro 5-4864. Flumazenil and 1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinoline carboxamide (PK 11195), which are selective antagonists of central- and peripheral-type benzodiazepine receptors, respectively, dose dependently blocked the inhibition of isoprenaline-induced amylase release by diazepam. At a concentration of 10(-5) M, flumazenil and PK 11195 restored amylase release to approximately 75% of that in the presence of isoprenaline alone. The combination of both antagonists completely prevented the inhibition by diazepam. Similarly, the inhibitory responses of clonazepam and Ro 5-4864 were completely blocked by flumazenil and PK 11195, respectively. These results suggest that, in rat parotid acinar cells, benzodiazepines inhibit beta-adrenoceptor and muscarinic receptor-stimulated amylase release and that both central- and peripheral-type benzodiazepine receptors contribute to this inhibitory regulation.

Adenovirus-mediated gene expression in isolated rat pancreatic acini and individual pancreatic acinar cells

In this study we have examined the feasibility of using replication-deficient recombinant adenoviral vectors to transfer and express genes in pancreatic acinar cells in vitro. We infected primary cultures of both isolated pancreatic acini and individual acinar cells with a recombinant adenovirus containing the coding sequence for beta-galactosidase. Our data demonstrate that recombinant adenoviruses readily infect pancreatic acinar cells in vitro. Close to 100% infection and maximal beta-galactosidase expression were obtained, when acini or acinar cells were infected with 5x10(6) or 10(6) plaque-forming units (pfu) of virus per millitre of acini or acinar cell suspension, respectively. Examination of the time-course of beta-galactosidase expression showed that there was a lag of approximately 6 h before beta-galactosidase levels increased. Thereafter beta-galactosidase expression increased rapidly. By 20 h post-infection beta-galactosidase activity had increased from undetectable levels to 2.5-3.0 units/mg of cellular protein. Acini/acinar cells maintained a robust secretory response after adenoviral infection. The cholecystokinin-octapeptide (CCK8) dose/response curves for amylase secretion for acini and acinar cells infected with 5x10(5) and 1x10(5) pfu/ml of virus, respectively, were biphasic, with maximal amylase secretion being stimulated by 1 nM CCK8. In addition, the dose/response curves were identical to those obtained from control, sham-infected, acini/acinar cells. Our findings indicate that replication-deficient recombinant adenoviral vectors will be excellent tools to transfer and express genes in isolated pancreatic acini or acinar cells.

Protective effects of a PAF receptor antagonist and a neutrophil elastase inhibitor on multiple organ failure induced by cerulein plus lipopolysaccharide in rats

The inhibitory effects of YM264, a selective platelet activating factor (PAF) receptor antagonist, and 2-(3-methylsulfonylamino-2-oxo-6-phenyl-1,2-dihydro-1-pyridyl)-N-( 3,3,3-trifluoro-1-isopropyl-2-oxopropyl)acetamide (compound 1), a neutrophil elastase inhibitor, on mortality, and pancreatic, hepatic, renal and pulmonary dysfunction were evaluated in a rat model of multiple organ failure (MOF) accompanying acute pancreatitis. MOF was produced by intraperitoneal injection of lipopolysaccharide (LPS, 30 mg/kg) in rats with cerulein-induced pancreatitis. LPS dose-dependently increased the mortality in rats with or without pancreatitis. The threshold dose which produced death in rats without pancreatitis was 30 mg/kg. This same dose evoked death in more than 40% of rats with pancreatitis. Time-course changes in serum enzyme and organ myeloperoxidase (MPO) levels were first examined in rats with induced MOF, and the results were compared with those in rats treated with only LPS or cerulein. Pancreatic weight, and serum amylase and lipase levels significantly increased in rats with cerulein-induced pancreatitis despite the presence or absence of LPS, but recovery of these pancreatic dysfunctions was slower in the group given LPS. However, serum GOT, GPT, BUN and creatinine levels were significantly elevated only in MOF rats. In the MOF rats, the MPO level in the lung was significantly elevated and arterial oxygen pressure was decreased, indicating that infiltration of neutrophils into the lung might be involved in pulmonary dysfunction. However, the MPO levels in the pancreas and kidney in the MOF rats were not remarkably different from those in normal rats. The inhibitory effects of YM264 and compound 1 on mortality and organ dysfunction were examined in this MOF model. The 24-h survival rate for rats prophylactically and therapeutically treated with an intravenous infusion of YM264 at 0.1 mg/kg h was significantly higher than that of controls. The 24-h survival rate for rats treated prophylactically by intravenous infusion of 2 mg/kg h of compound 1 was significantly higher than that of control, whereas a beneficial dose of compound 1 was 5 mg/kg h in therapeutically treated rats. Prophylactic treatment with YM264 (0.1 mg/kg h) and compound 1 (2 mg/kg h) ameliorated organ dysfunction in rats with MOF. In conclusion, pancreatic, hepatic, renal and pulmonary dysfunctions are observed in this rat MOF model. The PAF receptor antagonist and neutrophil elastase inhibitor reduce the mortality rate in rats with MOF due to their inhibitory effects on organ dysfunction, indicating that PAF and neutrophil elastase may play important roles in the development of MOF. These results in the present model are largely consistent with those in patients with MOF, indicating that this model is suited for MOF in humans and may be used as a model to test new therapeutic approaches.

Augmentation of the inhibitory effect of FK480, a CCK-A receptor antagonist, on pancreatic exocrine secretion by achlorhydria

The effect of intraluminal acid and cholecystokinin (CCK) receptor blockade on the pancreatic secretory response was examined in rats. Blockade of gastric acid secretion by YM022 (CCK-B receptor antagonist) or famotidine (histamine-2 receptor antagonist) resulted in a significant suppression of casein-stimulated pancreatic exocrine secretion as determined by juice volume and amylase secretion. Ligation of the gastric pylorus, which leads to complete prevention of gastric acid from entering the duodenum, also suppressed pancreatic exocrine secretion. FK480 (CCK-A receptor antagonist) inhibited pancreatic exocrine secretion dose dependently at doses of 0.01-1.0 mg/kg. When submaximal doses of FK480 and YM022 were treated concomitantly, pancreatic exocrine secretion was inhibited more profoundly than when treated solely. Hydrochloric acid (HCl; 0.05 N), injected into the duodenum, stimulated pancreatic exocrine secretion to a level comparable to that exhibited by intraduodenal casein. This effect of HCl was inhibited by FK480 (1.0 mg/kg) but not by YM022 (1.0 mg/kg). These findings suggest that inhibition of gastric acid secretion leads to the suppression of pancreatic exocrine secretion through mechanisms mediated by CCK-A receptors.

Atrial natriuretic factor-induced amylase output in the rat parotid gland appears to be mediated by the inositol phosphate pathway

In previous in vivo studies we have reported that atrial natriuretic factor enhanced induced salivary secretion and increased isoproterenol-induced amylase release in the rat suggesting that, ANF effect could be mediated by phosphatidylinositol hydrolysis. In the present work, the effect of ANF on rat parotid tissue incubated in vitro was investigated with the aim to assess whether the phosphoinositol pathway was involved in ANF intracellular signaling in the parotid gland. Results showed that ANF induced a dose dependent increase in amylase fractional release, which was lower than that evoked by any concentration of isoproterenol. Furthermore 100 nM ANF enhanced isoproterenol-evoked amylase release. The effect of ANF was not affected in the presence of propranolol suggesting the noninvolvement of the beta adrenergic receptor, which is the main stimulus for the output of the enzyme in the parotid gland. However, ANF increased phosphatidylinositol hydrolysis, which implies an increase in intracellular calcium, which is necessary for the achievement of maximal response in amylase release. This effect was abolished in the presence of neomycin supporting ANF direct stimulation of phospholipase C. These results suggest the involvement of the C type natriuretic peptide receptor coupled to phospholipase C in ANF evoked amylase release and ANF enhancement of the isoproterenol-induced output of the enzyme.

Cyclic AMP potentiates substance P-induced amylase secretion by augmenting the effect of calcium in the rat parotid acinar cells

Potentiation of amylase secretion by the combination of isoproterenol and substance P was examined in perfused rat parotid acinar cells. Combined additions of substance P and isoproterenol evoked biphasic changes in amylase secretion, an initial large peak and the following sustained plateau: the magnitudes of the both responses were higher than the sum of the responses induced by each agonist alone. Isoproterenol also increased the maximum response and the apparent affinity (EC50) for substance P to evoke the initial peak response; the EC50 values were about 20 and 0.8 nM, respectively, in the absence and the presence of isoproterenol. On the other hand, 1 nM substance P was sufficient for evoking the maximum potentiation of the sustained plateau response. Substance P did not change the EC50 for isoproterenol. The effect of isoproterenol was mimicked with dibutyryl cyclic AMP and agonists that increase parotid cyclic AMP. Omission of Ca2+ or addition of 5 mM nickel chloride almost completely abolished the potentiation of the sustained plateau, but little decreased that of the initial peak. Depletion of Ca2+ in InsP3-sensitive intracellular stores with thapsigargin, on the other hand, decreased the initial peak response, but not the sustained plateau, to substance P. The potentiation was also observed between isoproterenol and Ca2+ ionophores. Switching to the solutions containing higher concentrations of Ca2+ during the continuous stimulation with isoproterenol or IBMX evoked a large, but transient, response of amylase secretion. Time course of changes in amylase secretion induced by isoproterenol and substance P in combination was very similar to that of substance P, but not of isoproterenol. Isoproterenol did not enhance the effect of substance P on [Ca2+]i. These results show that the potentiation is mainly, if not totally, caused by cyclic AMP-induced enhancement of the potency and the efficacy in the pathway regulated by Ca2+.

Effects of islet hormones on nerve-mediated and acetylcholine-evoked secretory responses in the isolated pancreas of normal and diabetic rats

This study employs the pancreas of normal and diabetic rats to investigate the relationship between the endocrine and exocrine pancreas in the control of exocrine secretion employing enzyme and immunohistochemical and physiological techniques. Acetylcholine esterase (ACh-E) positive nerves were distributed in the interacinar regions of the pancreas lying close to the exocrine cells. There was no difference between the cholinergic innervation of the pancreas in normal and diabetic rat. Insulin (INS) immunopositive cells were observed in the peripheral and central portions of the Islet of Langerhans in the pancreas of normal rat. In the diabetic animals the number of INS-positive cells were decreased. In contrast, glucagon (GLU) and somatostatin (SOM)-immunopositive cells were identified mainly in the peripheral parts of the Islets of Langerhans and their numbers increased markedly in the diabetic pancreas. Insulin alone had no significant effect on amylase secretion in the normal pancreas whereas GLU and SOM evoked small increases in amylase out compared to basal. In contrast, the islet hormones have no detectable secretory effect on the diabetic pancreas compared to control. Both electrical field stimulation (EFS) of intrinsic secretomotor nerves and exogenous application of acetylcholine (ACh) resulted in marked increases in amylase secretion. In pancreatic acini and acinar cells ACh evoked dose-dependent increases in amylase release. In normal pancreatic segments a combination of either INS or GLU with EFS or ACh resulted in marked potentiation of amylase output. In contrast, SOM inhibited the EFS-evoked amylase output but enhanced the secretory response to ACh. In pancreatic acini and acinar cells from normal rat and in pancreatic segments from diabetic rats, the islet hormones had no potentiating effect on the ACh-evoked secretory response. Similarly, in the diabetic rat the islet hormone had no effect on EFS-evoked amylase output. In fura-2 loaded pancreatic acinar cells ACh-induced a marked increase in intracellular free calcium concentration [Ca2+]i compared to basal. Either INS or GLU, but not SOM, elicited a small increase in [Ca2+]i. Combining either INS or GLU with ACh resulted in a potentiation of [Ca2+]i compared with ACh alone. In contrast, SOM had no significant effect on the ACh-induced [Ca2+]i compared to the response obtained with ACh alone. In pancreatic acinar cells of diabetic rat ACh-elicited similar magnitude of [Ca2+]i compared to acinar cells of normal rat. However, when the islet hormones were combined with ACh there was no enhancement of [Ca2+]i compared to ACh alone. The results indicate that the potentiation of either EFS or ACh-evoked secretory responses by the islet hormones seem to occur only in pancreatic segments which have intact viable Islets of Langerhans and not in either acini and acinar cells or from the pancreas of diabetic rat. Moreover, it is apparent that cellular Ca2+ is involved with the interaction of ACh with either INS or GLU.

Thermostable, high salt-tolerant amylase from Bacillus megaterium VUMB-109

A bacterial strain, Bacillus megaterium VUMB-109, has been isolated and identified which produces salt-tolerant, thermostable amylase (16 U/ml culture filtrate). Cultural conditions such as carbon and nitrogen sources, metal ions, temperature and pH have been optimized for enzyme production. The partially purified enzyme was active over a wide range of pH (4.5-10) and exhibited maximum activity at 95 degrees C, retaining 90% original activity at 100 degrees C. Partially purified enzyme was stable at 70 degrees C for 60 min. The enzyme was stable in NaCl up to 5m over 24 h without losing its original activity.

Spontaneous and cholecystokinin-octapeptide-promoted regeneration of the pancreas following L-arginine-induced pancreatitis in rat

CONCLUSION

In L-arginine (Arg)-induced pancreatitis, evidence of acute inflammation was observed on d 1-3. Continuous tissue atrophy became visible at the sites of previous pancreatic necrosis, with simultaneous regeneration of the pancreas, mainly around the Langerhans islets. Administration of low doses of cholecystokinin-octapeptide (CCK-8) increased the inflammatory signs of pancreatitis in the early phase, but subsequently diminished the level of atrophy and accelerated the processes of regeneration in this model of pancreatitis.

BACKGROUND

The aim of this work was to study the regenerative processes following Arg-induced pancreatitis in rats. Besides the spontaneous regeneration, the effects of low doses of CCK-8 on the laboratory and morphologic parameters in this type of experimental pancreatitis were investigated.

METHODS

Male Wistar rats were divided into three groups. In group I, the rats received 200 mg/100 g body weight of Arg i.p. twice, at an interval of 1 h, and 0.5 mL saline was administered s.c. twice daily. In group II, besides the same amount of Arg, the rats received 1 microgram/kg of CCK-8 s.c. in 0.5-mL saline twice daily (7 AM and 7 PM). In the control animals (group III), an identical amount of glycine was administered i.p. instead of Arg at the same times. The rats were examined on d 1, 3, 7, 14, and 28 after pancreatitis induction. The pancreatic weight/body weight ratio (pw/bw) was calculated in each case. The serum levels of amylase, and glucose and the pancreatic contents of soluble protein, trypsin, amylase and DNA were determined, and histologic examinations were performed.

RESULTS

In groups I and II, both pw/bw (3.5 +/- 0.2 mg/g and 4.1 +/- 0.28 mg/g, respectively) and the serum amylase level (8900 +/- 560 IU/L and 11100 +/- 1390 IU/L, respectively) were significantly elevated on d 1 vs group III (2.1 +/- 0.06 mg/g and 5562 +/- 373 IU/L, respectively). Pw/bw was significantly decreased in groups I (0.96 +/- 0.12 mg/g, 0.8 +/- 0.1 mg/g, and 1.8 +/- 0.1 mg/g, respectively) and II (1.4 +/- 0.15 mg/g, 1.7 +/- 0.2 mg/g, and 1.95 +/- 0.1 mg/g, respectively) on d 7, 14, and 28 vs group III (2.6 +/- 0.3 mg/g, 3.1 +/- 0.15 mg/g, and 2.7 +/- 0.1 mg/g, respectively), whereas in group II it was significantly elevated vs. group I on d 7 and 14. The pancreatic contents of soluble protein, DNA, trypsin and amylase were significantly decreased on d 3-14 in groups I and II vs group III. The pancreatic DNA level was significantly elevated in group II (1.23 +/- 0.2 mg/pancreas) vs group I (0.7 +/- 0.1 mg/pancreas) on d 7. In group II, the soluble protein (73.1 +/- 15.5 mg/pancreas) and amylase (1104 +/- 160 IU/pancreas) levels were significantly elevated on d 14 as was that of trypsin (27.2 +/- 3.1 IU/pancreas) on d 28, vs group I (26.4 +/- 5.3 mg/p, 525 +/- 111 IU/pancreas, and 16.3 +/- 1.1 IU/pancreas, respectively). On histologic sections, the signs of acute inflammation of the pancreas were more pronounced in group II than in group I on d 1-3. After that time, in spite of the progressive atrophy of the pancreas, the signs of tissue repair were more expressed in group II.

Benfluorex, a hypotriglyceridemic drug, reduces lipid peroxidation and alleviates adverse metabolic complications of copper deficiency

The pathologies associated with copper deficiency in rats fed fructose may be induced, in part, by hypertriglyceridemia and lipid peroxidation. Reducing triacylglycerol levels in plasma may result in lowering lipid peroxidation, which in turn could ameliorate metabolic effects resulting from the combination of fructose feeding and copper deficiency. Benfluorex, a hypolipidemic factor able to reduce hypertriglyceridemia, was administered to weanling male rats fed either copper-deficient (0.6 microgram Cu/g) or adequate (6.0 micrograms Cu/g) diets containing fructose as the sole dietary carbohydrate. In copper-deficient rats, benfluorex (50 micrograms.kg-1.d-1) reduced plasma triacylglycerols from 45 to 31 mg/dL, reduced lipid peroxidation by approximately 50%, and prevented the enlargements of heart and liver size and the atrophy of the pancreas, and ameliorated anemia. It is suggested that lipid peroxidation associated with hypertriglyceridemia may be responsible for the pathologies induced by the combination of fructose consumption and copper deficiency.