Methonexate is one of the well known anti-cancer chemotherapeutic agents and exerts its action by inhibiting mitoses by inhibition of nucleic acid synthesis. Its effect on actively proliferating normal and pathologic tissues have been well documented. However, little information is available on its effect on tissue which shows no active mitoses but does have a very active metabolic process, such as the pancreas. The present study investigated the histochemical and ultrastructural changes which take place within 24 hours after a single intraperitoneal injection of methotrexate. Using a light microscope for observation, no .specific or constant alteration was noted except for a mild acinar cell dissociation 18 hours after the injection. However, electron microscopic observations showed that several organelles of pancreatic acinar cell revealed ultrastructural changes such as vesiculation and dilation of the cisternae of endoplasmic reticulum, and the appearance of autophagic vacuoles which contained cellular organelles, and showed hyperplasia and dilation of Golgi complexes. The nuclei and zymogen granules were not significantly altered. The changes of endoplasmic reticulum were ,distinctly seen from 1 hour after the injection and were most severe at 6 hours. Autophagic vacuoles appeared at 6 hours and had progressively increased in number and size 18 hours after the injection. Similar changes were also reported in experimental animals which were treated with several cytotoxic agents. According to this study, it is evident that a single administration of methotrexate within short time interval induced a series of ultrastructural alterations in several organelles of the pancreatic acinar cells. It is not clear as yet whether or not this is a specific reaction of cells to methotrexate.
Animals ; Female ; Male ; Methotrexate/*pharmacology ; Pancreas/cytology/*drug effects ; Rats

OBJECTIVETo explore the impact of 5-fluorouracil (5-FU) on glucose metabolism and pancreatic pathology.

METHODSTwenty Wistar rats were divided into 5-FU group(n=10, chemotherapy was administered intraperitoneally to animals at a dose of 20 mg/kg daily for continuous 5 days) and control group (n=10, sodium chloride was administered intraperitoneally to animals with the same dose at the same time ). Glucose tolerance was evaluated 2 and 7 days following 5-FU treatment by serial measurement of blood glucose before and after an oral glucose load. Plasma insulin concentration was determined by radioimmunoassay. Pancreatic pathology was examined with morphological method and the ultrastructural changes of β cells were observed by transmission electron microscope.

RESULTSFasting blood glucose level was significantly higher in the 5-FU group than that in the control group [(7.6±0.9) mmol/L vs. (4.6±0.6) mmol/L at day 2; (8.9±1.0) mmol/L vs. (4.7±0.6) mmol/L at day 7, P<0.01]. Insulin releasing test indicated that the early phase insulin response to glucose load was significantly diminished in animals treated with 5-FU at day 2. Insulin level was significantly lower in the 5-FU group than that in the control group at 30 min (P<0.01). The peak secretion time of plasma insulin in 5-FU group was at 60 min, similar to the control group; and plasma insulin level decreased more slowly. Plasma insulin level was higher in 5-FU groups than in control groups on 120 min and 180 min. At day 7, Insulin level was lower in the 5-FU group than that in the control group on 60 min, and the peak secretion time of plasma insulin was delayed to 120 min. Plasma insulin level was significantly increased in 5-FU group than that in control group on 180 min(P<0.01). No gross histopathological damage to the pancreas was observed at day 2 and 7 following administration of 5-FU. The structural changes of mitochondria were mainly the quantities of secretory granule diminished at day 7 under transmission electron microscope. Dilated rough endoplasmic reticula, swollen mitochondria, and the presence of adipose drops in lysosomes were found in few cells.

CONCLUSIONS5-FU-induced hyperglycemia appears to be mediated in part by a relatively deficient insulin secretion to glucose stimulation. A relative deficiency in insulin secretion following 5-FU treatment appears to be related to β cells function impairs with islet cell ultrastructural changes induced by 5-FU.

Animals ; Blood Glucose ; drug effects ; metabolism ; Female ; Fluorouracil ; pharmacology ; Insulin ; blood ; Male ; Pancreas ; drug effects ; pathology ; Rats ; Rats, Wistar

AIMTo know the effect of cysteamine on the pancreatic secretion and enzyme activity in geese.

METHODSEight adult geese fitted chronic pancreatic and duodenal cannulas were used to evaluate the effect of cysteamine (CS) on the pancreatic secretion and enzyme activity. The experiment was consist of control and treated phase. CS was added in the diet at the dosage of 100 mg/kg bw on the first day of treated phase. The birds were free fed at daytime (8:00-20:00) and fasted at nighttime (20:00-8:00). The pancreatic juice samples were collected continuously for three days in each phase.

RESULTSCS increased the average rate of pancreatic secretion by 240.16% (P < 0.01), in which that of daytime was elevated by 234.45% (P < 0.01), while that of nighttime elevated by 253.70% (P < 0.01). The secretion volume at daytime was more than that of night. CS increased trypsin activity by 49.05% (P < 0.01), whereas lipase and amylase activity was reduced by 25.44% (P < 0.01) and 21.95% (P < 0.01) separately. The one hour total activity of trypsin, lipase and amylase were elevated by 406.88% (P < 0.01), 153.58% (P < 0.01) and 166.59% (P < 0.01) respectively. Ratios of pancreatic secretion were different between day and night.

CONCLUSIONThese results indicate that CS can affect the pancreatic juice secretion and pancreatic enzyme activity by depleting the somatostatin, so that benefits to improve the digestive foundation and supply more nutrition for quickly growing in geese.

Animals ; Cysteamine ; pharmacology ; Geese ; physiology ; Pancreas ; drug effects ; enzymology ; secretion ; Pancreatic Juice ; secretion ; Pancreatin ; metabolism

OBJECTIVETo evaluate the consequence of oral administration of Calliandra portoricensis (C. portoricensis) leaf extract on the stomach and pancreas in Swiss albino mice.

METHODSThree groups of mice (B, C and D) were treated with 4 mg/kg of C. portoricensis extract. Group A was the control and received an equivalent volume of distilled water. Group B received C. portoricensis leaf extract for 7 days, Group C received C. portoricensis leaf extract for 14 days, and Group D received C. portoricensis leaf extract for 28 days. At different stages in the study, the mice were sacrificed and the stomach and pancreas were excised and fixed in 10% formol saline for histological analysis.

RESULTSThe result showed a normal microstructural outline in groups B and C as compared with the control. However, animals in group D showed disorganization of the mucosa and discontinuation of epithelial lining of the stomach while the islets of Langerans in the pancreas were at various degree of degeneration as compared with the control mice.

CONCLUSIONSThe present finding suggests that chronic administration (28 days as seen in this study) of C. portoricensis leaf extract may inhibit the proper function of the stomach and pancreas.

Animals ; Fabaceae ; chemistry ; Mice ; Organ Size ; drug effects ; Pancreas ; drug effects ; pathology ; Plant Extracts ; administration & dosage ; pharmacology ; Plant Leaves ; chemistry ; Stomach ; drug effects ; pathology

To determine whether exocrine pancreatic secretion is regulated by endogenous somatostatin, somatostatin deficiency was induced by cysteamine. Rats were subcutaneously administered a single dose of cysteamine (30 mg/100 g body weight) 12 hr before experiment. Anesthetized rats were prepared with cannulation into bile duct, pancreatic duct, duodenum, and jugular vein and pancreatic juice was collected. For in vitro study, isolated pancreata of rats, pretreated with cysteamine, were perfused with an intraarterial infusion of Krebs-Henseleit solution (37 degrees C) at 1.2 mL/min, and pancreatic juice was collected in 15-min samples. In vivo experiment of the rat, the mean basal pancreatic secretions, including volume, bicarbonate, and protein output were significantly increased from 18.4+/-0.5 microL/30 min, 0.58+/-0.05 microEq/30 min, and 214.0+/-26.1 microg/30 min to 51.6+/-3.7 microL/30 min, 1.52+/-0.11 microEq/30 min, and 569.8+/-128.9 microg/30 min, respectively (p<0.05). In the isolated perfused pancreas, cysteamine also resulted in a significant increase in basal pancreatic secretion (p<0.05). Simultaneous intraarterial infusion of octreotide (10 pmol/hr) to isolated pancreata partially reversed the effect of cysteamine on basal pancreatic secretion. These findings suggest that endogenous somatostatin play an important role on the regulation of basal pancreatic exocrine secretion.
Animal ; Cysteamine/pharmacology* ; Hormone Antagonists/pharmacology* ; Hormones, Synthetic/pharmacology ; In Vitro ; Male ; Octreotide/pharmacology ; Pancreas/secretion ; Pancreas/drug effects* ; Perfusion ; Rats ; Rats, Sprague-Dawley ; Somatostatin/antagonists & inhibitors*

Pancreatic polypeptie (PP) is released from the pancreas in response to vagal stimulation. Amongst other effects, PP has been reported to inhibit pancreatic exocrine function. Apart from any potential physiological role, such inhibition could have important consequences for in vitro studies of pancreatic function employing acetylcholine as a stimulus. We have therefore tested the effect of bovine PP on two in vitro pancreatic preparations: the incubated, uncinate pancreas of young rats and the perfused cat pancreas. In the former, PP (10(-10)-10(-8)M) had little or no effect on enzyme discharge or45Ca efflux under basal conditions or during stimulation with caerulein, CCK-PZ or acetylcholine. In the perfused cat pancreas, similar concentrations of PP were also without effect on fluid secretion evoked by secretin infusion, or enzyme discharge evoked by CCK-PZ injection or infusion. We conclude that bovine PP has no direct effects on the cellular mechanisms responsible for pancreatic electrolyte secretion or enzyme discharge in the species studied.
Acetylcholine/pharmacology ; Amylases/secretion* ; Animal ; Caerulein/pharmacology ; Calcium/metabolism* ; Cats ; Cholecystokinin/pharmacology ; Electrolytes/secretion* ; In Vitro ; Pancreas/drug effects ; Pancreas/metabolism* ; Pancreatic Polypeptide/pharmacology* ; Perfusion ; Rats ; Secretin/pharmacology

OBJECTIVETo study the relationship between neuropeptide Y (NPY) and diabetes by examining the content and distribution of NPY and its mRNA expression in the hypothalamus and pancreas of STZ-diabetic rats.

METHODSThirty Wistar rats were randomly divided into 3 groups (diabetic group, diabetic insulin treatment group, and control group). After feeding for 24 weeks, the rats were sacrificed. The expression of NPY in the hypothalamus and pancreas was detected with immunohistochemistry and in situ hybridization.

RESULTS(1) The hypothalamic content of NPY and its mRNA were significantly increased in STZ-diabetic rats in comparison with normal controls. Increased expression of NPY mRNA was found only in the arcuate nucleus and not in the paraventricular nucleus in diabetic rats, suggesting that NPY was produced in the arcuate nucleus. (2) The hypothalamic content of NPY and its mRNA in STZ-diabetic rats were visibly reduced after insulin treatment compared with that in untreated diabetic rats. This supports the hypothesis that insulin deficiency in the brain may be responsible for increased hypothalamic NPY gene expression in diabetic rats. (3) The increase of hypothalamic NPY in STZ diabetic rats associated with hyperphagia and polydipsia could be reversed by insulin replacement, suggesting that increased hypothalamic NPY contributes to the pathophysiological progress of the diabetic state. (4) The present study demonstrated for the first time that the content of NPY and its mRNA in the pancreas was increased in STZ-diabetic rats, and that the distribution of NPY-positive cell in islets was changed from the periphery to the whole islet. The content and distribution of NPY and its mRNA in islets were not changed by insulin treatment.

CONCLUSIONIncreased NPY in the hypothalamus results in hypophagia and polydipsia, while the implication of increased NPY in the pancreas of diabetic rats is not clear.

Animals ; Blood Glucose ; drug effects ; Diabetes Mellitus, Experimental ; drug therapy ; genetics ; metabolism ; Drinking ; drug effects ; Eating ; drug effects ; Female ; Gene Expression Regulation ; drug effects ; Hypothalamus ; drug effects ; metabolism ; Immunohistochemistry ; In Situ Hybridization ; Insulin ; therapeutic use ; Neuropeptide Y ; drug effects ; genetics ; metabolism ; Pancreas ; drug effects ; metabolism ; RNA, Messenger ; drug effects ; genetics ; metabolism ; Rats ; Rats, Wistar

PURPOSE: In non-excitable cells, which include parotid and pancreatic acinar cells, Ca(2+) entry is triggered via a mechanism known as capacitative Ca(2+) entry, or store-operated Ca(2+) entry. This process is initiated by the perception of the filling state of endoplasmic reticulum (ER) and the depletion of internal Ca(2+) stores, which acts as an important factor triggering Ca(2+) entry. However, both the mechanism of store-mediated Ca(2+) entry and the molecular identity of store-operated Ca(2+) channel (SOCC) remain uncertain. MATERIALS AND METHODS: In the present study we investigated the Ca(2+) entry initiation site evoked by depletion of ER to identify the localization of SOCC in mouse parotid and pancreatic acinar cells with microfluorometeric imaging system. RESULTS: Treatment with thapsigargin (Tg), an inhibitor of sarco/endoplasmic reticulum Ca(2+)-ATPase, in an extracellular Ca(2+) free state, and subsequent exposure to a high external calcium state evoked Ca(2+) entry, while treatment with lanthanum, a non-specific blocker of plasma Ca(2+) channel, completely blocked Tg-induced Ca(2+) entry. Microfluorometric imaging showed that Tg-induced Ca(2+) entry started at a basal membrane, not a apical membrane. CONCLUSION: These results suggest that Ca2+ entry by depletion of the ER initiates at the basal pole in polarized exocrine cells and may help to characterize the nature of SOCC.
Animals ; Calcium/*metabolism ; Calcium Channels/drug effects/metabolism ; Cells, Cultured ; Endoplasmic Reticulum/drug effects/*metabolism ; Mice ; Mice, Inbred ICR ; Microscopy, Fluorescence ; Pancreas/cytology/drug effects/*metabolism ; Parotid Gland/cytology/drug effects/*metabolism ; Thapsigargin/pharmacology

OBJECTIVETo investigate the effect of Ca(2+) on lipopolysaccharide (LPS)-induced NF-kappa B activation in pancreatic acinar cells and the role of NF-kappa B in LPS-induced acinar cell injury.

METHODSMale rat pancreatic acinar cells were isolated by collagenase digestion, then exposed to varying concentrations of LPS (from 1 to 20 mg/L) in the presence or absence of EGTA. At various time points (30 minutes, 1 hour, 2 hours, 4 hours and 10 hours) after treatment with the agents, cell viability was determined by MTT. Nuclear translocation of NF-kappa B's subunit p65 was visualized by immunofluorescence staining and nuclei protein was extracted to perform EMSA which was used to assay the activity of NF-kappa B binding to the DNA sequence containing the recognition site of NF-kappa B.

RESULTSLPS induced cell damage in a time- and concentration-dependent manner while EGTA attenuated LPS-induced cell damage (P < 0.05). NF-kappa B p65 immunofluorescence staining had increased intensity in the cytoplasm and indicated that nuclear translocation occurred within 30 minutes and its zenith was reached at 1 hour after LPS (10 mg/L) treatment. Testing of NF-kappa B DNA binding activity showed the same alteration phase as p65 immunofluorescence staining. NF-kappa B activation preceded the pathological alteration of pancreatic acinar cells. The Ca(2+) chelator EGTA inhibited LPS-induced NF-kappa B activation.

CONCLUSIONSNF-kappa B activation is an important early event in LPS-induced injury to pancreatic acinar cells. Ca(2+) is an important mediator in the process of LPS-induced NF-kappa B activation.

Animals ; Calcium ; pharmacology ; Lipopolysaccharides ; pharmacology ; Male ; NF-kappa B ; physiology ; Pancreas ; cytology ; drug effects ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo discuss the effect of Zea mays L. saponin (ZMLS) on ultrastructure of kidney and pancreas in the diabetes rats induced by streptozocin.

METHODThe diabetic rat model was established by injections of STZ, blood glucose, the ultrastructure of the kidney and pancreas were observed.

RESULTCompared with the model group, the large, middle-dose ZMLS groups and melbinum group could remarkably decrease the blood glucose (P < 0.01), the large, middle, small-dose ZMLS groups could remarkably prevent the pancreatic islet beta-cell from the injury induced by Streptozotocin. Melbinum and the large, middle-dose ZMLS groups could remarkably increase mitochondrial Vv, deltam and euchromatin Vv (P < 0.01), and significantly decrease the delta, Nucleus delta and heterochromatin Vv (P < 0.01). The small dose of ZMLS obviously increases mitochondrial Vv (P < 0.05).

CONCLUSIONZMLS showed good effect on decreasing blood glucose and protection action on the kidney and pancreas injury of induced by STZ.

Animals ; Blood Glucose ; drug effects ; Diabetes Mellitus ; drug therapy ; Diabetes Mellitus, Experimental ; drug therapy ; Humans ; Kidney ; drug effects ; ultrastructure ; Male ; Pancreas ; drug effects ; ultrastructure ; Plant Extracts ; administration & dosage ; Rats ; Rats, Wistar ; Saponins ; administration & dosage ; Streptozocin ; Zea mays ; chemistry