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1.
Primiparous ewes (n=32) were assigned to dietary treatments in a 2×2 factorial arrangement to determine effects of nutrient restriction and melatonin supplementation on maternal and fetal pancreatic weight, digestive enzyme activity, concentration of insulin-containing clusters and plasma insulin concentrations. Treatments consisted of nutrient intake with 60% (RES) or 100% (ADQ) of requirements and melatonin supplementation at 0 (CON) or 5 mg/day (MEL). Treatments began on day 50 of gestation and continued until day 130. On day 130, blood was collected under general anesthesia from the uterine artery, uterine vein, umbilical artery and umbilical vein for plasma insulin analysis. Ewes were then euthanized and the pancreas removed from the ewe and fetus, trimmed of mesentery and fat, weighed and snap-frozen until enzyme analysis. In addition, samples of pancreatic tissue were fixed in 10% formalin solution for histological examination including quantitative characterization of size and distribution of insulin-containing cell clusters. Nutrient restriction decreased (P⩽0.001) maternal pancreatic mass (g) and α-amylase activity (U/g, kU/pancreas, U/kg BW). Ewes supplemented with melatonin had increased pancreatic mass (P=0.03) and α-amylase content (kU/pancreas and U/kg BW). Melatonin supplementation decreased (P=0.002) maternal pancreatic insulin-positive tissue area (relative to section of tissue), and size of the largest insulin-containing cell cluster (P=0.04). Nutrient restriction decreased pancreatic insulin-positive tissue area (P=0.03) and percent of large (32 001 to 512 000 µm2) and giant (⩾512 001 µm2) insulin-containing cell clusters (P=0.04) in the fetus. Insulin concentrations in plasma from the uterine vein, umbilical artery and umbilical vein were greater (P⩽0.01) in animals receiving 100% requirements. When comparing ewes to fetuses, ewes had a greater percentage of medium insulin-containing cell clusters (2001 to 32 000 µm2) while fetuses had more (P<0.001) pancreatic insulin-positive area (relative to section of tissue) and a greater percent of small, large and giant insulin-containing cell clusters (P⩽0.02). Larger insulin-containing clusters were observed in fetuses (P<0.001) compared with ewes. In summary, the maternal pancreas responded to nutrient restriction by decreasing pancreatic weight and activity of digestive enzymes while melatonin supplementation increased α-amylase content. Nutrient restriction decreased the number of pancreatic insulin-containing clusters in fetuses while melatonin supplementation did not influence insulin concentration. This indicated using melatonin as a therapeutic agent to mitigate reduced pancreatic function in the fetus due to maternal nutrient restriction may not be beneficial.  相似文献   

2.
Cholecystokinin-8 (CCK-8) causes exocrine pancreatic hypertrophy and hyperplasia. High doses of the CCK analogue cerulein causes necrosis and an inflammatory response in the pancreas. We have studied the pancreatic growth response in rats after administration of CCK-8 for 3 days, given either intermittently (20-80 microg/kg) twice a day, or continuously (2.4-48 microg/kg per 24 h). Plasma CCK-8 levels, pancreatic wet weight, water, protein and DNA contents and the pancreatic caspase-3 activity were measured. Cell proliferation was visualized by [3H]thymidine incorporation and apoptosis by TUNEL reaction. Continuous administration of CCK-8 dose-dependently increased the plasma CCK levels, the pancreatic wet weight, protein and DNA contents as well as thymidine labeling index, apoptotic index and caspase-3 activity. Intermittent injections of CCK-8 caused transient raises in plasma CCK, increased apoptotic index and caspase-3 activity, a dose-dependent increase in thymidine labeling but caused a dose-dependent reduction of pancreatic wet weight, protein, and DNA contents. It is concluded that CCK-8 causes both increased proliferation and apoptosis in the pancreas. In case of continuous administration of CCK-8, the proliferation outweighs the apoptosis causing hyperplasia but in the case of intermittent administration the opposite effect is seen.  相似文献   

3.
The effect of maternal diabetes (induced by i.p. injections of 40-50 mg/kg BW Streptozotocin on the day of mating) on TRH in the pancreas of newborn rats was studied. Determination of peptide alpha amidation activity and TRH precursor level on the day of birth revealed decreased biosynthesis of TRH resulting in profoundly (10 times) lower pancreatic TRH and TRH-OH concentrations in pups of diabetic rats. Pancreatic His-Pro-diketopiperazine (His-Pro-DKP) remained unaffected by maternal diabetes. The depression of pancreatic TRH was less profound 24 h later, and even elevated TRH was measured in the pancreas of pups of diabetic mothers on postnatal day 5. Short term postnatal starvation or nursing of intact pups by the diabetic foster mother did not affect pancreatic TRH. It could be postulated that postnatal TRH development in the rat pancreas is retarded by maternal diabetes, while His-Pro-DKP remains unaltered.  相似文献   

4.
Yuan Q  Chen L  Liu C  Xu K  Mao X  Liu C 《PloS one》2011,6(10):e25167
Epidemiological studies have linked intrauterine growth retardation (IUGR) to the metabolic diseases, consisting of insulin resistance, type 2 diabetes, obesity and coronary artery disease, during adult life. To determine the internal relationship between IUGR and islet β cell function and insulin sensitivity, we established the IUGR model by maternal nutrition restriction during mid- to late-gestation. Glucose tolerance test and insulin tolerance test (ITT) in vivo and glucose stimulated insulin secretion (GSIS) test in vitro were performed at different stages in IUGR and normal groups. Body weight, pancreas weight and pancreas/body weight of IUGR rats were much lower than those in normal group before 3 weeks of age. While the growth of IUGR rats accelerated after 3 weeks, pancreas weight and pancreas/body weight remained lower till 15 weeks of age. In the newborns, the fasting glucose and insulin levels of IUGR rats were both lower than those of controls, whereas glucose levels at 120 and 180 min after glucose load were significantly higher in IUGR group. Between 3 and 15 weeks of age, both the fasting glucose and insulin levels were elevated and the glucose tolerance was impaired with time in IUGR rats. At age 15 weeks, the area under curve of insulin (AUCi) after glucose load in IUGR rats elevated markedly. Meanwhile, the stimulating index of islets in IUGR group during GSIS test at age 15 weeks was significantly lower than that of controls. ITT showed no significant difference in two groups before 7 weeks of age. However, in 15-week-old IUGR rats, there was a markedly blunted glycemic response to insulin load compared with normal group. These findings demonstrate that IUGR rats had both impaired pancreatic development and deteriorated glucose tolerance and insulin sensitivity, which would be the internal causes why they were prone to develop type 2 diabetes.  相似文献   

5.
This study compared pancreatic tissue growth and functional changes during the first 3 postnatal days in piglets and rat pups. In piglets the absolute weight and the relative weight per unit body weight of the pancreas increased by 97 and 70%, respectively, while in rat pups the same parameters decreased by 33 and 48%, respectively, during this period. The specific activity of pancreatic amylase rose by 336% while that of trypsin, chymotrypsin and lipase remained at newborn level in piglets. In rat pups the specific activities of all enzymes measured declined by 61 to 92% during the first 3 postnatal days. The rate of postnatal pancreatic growth in the two species coincide with the levels of epidermal growth factor and insulin-like growth factors in maternal milk as reported in the literature, suggesting that milk-borne growth factors may stimulate pancreatic development in newborn animals.  相似文献   

6.
Intrauterine hyperglycemic environment could harm the fetus making it more susceptible to develop postnatal glucose intolerance. A possible mechanism is compromise of the fetal pancreatic development. We previously found that a high sucrose low copper diabetogenic diet induces type 2 diabetes in the Cohen diabetic sensitive rats, but not in the Sabra control rats. However, oxidative stress was observed in the placenta and term fetal liver of diabetic and nondiabetic controls. We now investigated whether the fetal pancreas is affected by this diet and whether the effects result from oxidative stress, maternal hyperglycemia, or both. Term fetal pancreases were evaluated for morphology, beta cells, oxidative stress, apoptosis, and DNA methylation. There were no microscopic changes in hematoxylin and eosin stained sections and beta cells immunostaining in the pancreas of fetuses of both strains. Fetuses of the sensitive strain fed diabetogenic diet had significantly higher activity of superoxide dismutase and catalase, elevated levels of low molecular weight antioxidants, and more intense immunostaining for nuclear factor kappa‐B and hypoxia inducing factor‐1α. Both strains fed diabetogenic diet had increased immunostaining for Bcl‐2‐like protein and caspase 3 and decreased immunostaining for 5‐methylcytosine in their islets and acini. Our data suggest that maternal diabetogenic diet alters apoptotic rate and epigenetic steady states in the term fetal pancreas, unrelated to maternal diabetes. Maternal hyperglycemia further increases pancreatic oxidative stress, aggravating the pancreatic damage. The diet‐induced insults to the fetal pancreas may be an important contributor to the high susceptibility to develop diabetes following metabolic intrauterine insults  相似文献   

7.
A radioimmunoassay for quantitation of the human pancreatic estrogen binding protein (hEBP) was developed using polyclonal rabbit hEBP antiserum and iodinated purified hEBP. Parallel dose-response curves were obtained when serial dilutions of human serum and of cytosols obtained from human pancreas, prostate and colon were analyzed simultaneously with serial dilutions of purified hEBP standard. Very high levels of hEBP (500-1000 mg/kg wet weight) were found in normal pancreas. High as well as medium levels were found in pancreatic carcinoma tissue and medium values (0.1-1 mg/kg wet weight) in prostate, colon and ovarian tissue. Other tissues and serum from healthy volunteers showed low values, usually below 0.1 mg/kg. When serial dilutions of rat pancreatic cytosol were analyzed in the hEBP assay, [125I]hEBP was displaced by the rat preparation, but the dose-response curves were not parallel to the standard curves, indicating similarity but non-identity between the estrogen binding proteins in human and in rat pancreas.  相似文献   

8.
Monodelphis domestica, a South American marsupial proposed as a laboratory animal, presents some characteristics that are favourable for research on the development of pancreatic tissue. Therefore, it is important to know if Monodelphis domestica is similar to other mammals concerning the cellular composition of the pancreas and if the different regions of the organ share similar morphologic features. In the present study the pancreas of ten adult male or female Monodelphis domestica were examined: serial paraffin sections were stained immunohistochemically using polyclonal antibodies against insulin or glucagon. The size of the immunoreactive area was measured with a computer-based image-analysing system differentiating lobus dexter, corpus pancreatis, and lobus sinister.

The islets' profiles varied in size and shape. The insulin-positive cells were mainly located in the centre of the islets, while the glucagon-positive cells were arranged at the islets' periphery. However, some glucagon-positive cells also occurred in the centre of most islets. On average, 0.66% of the entire pancreatic section area was insulin-positive, while 0.23% was glucagon-positive. Thus, the ratio between glucagon-positive and insulin-positive area was 1:2.9. Differences between the three pancreatic parts, lobus dexter, corpus pancreatis, and lobus sinister, were revealed. In general, the findings compared well with those of species that have a history as laboratory animals, i.e. mice, rats, cats, and dogs.  相似文献   


9.
10.
PACAP exerts multiple activities as a hormone and neurotransmitter, and has been proposed to play vital roles in a variety of neuronal functions. PACAP is also involved in insulin secretion from pancreatic beta-cells. Recently, we and other groups demonstrated that PACAP-deficient mice (PACAP(-/-)) are viable, but suffer from increased postnatal mortality. To ascertain whether this high mortality is rescued by overexpression of PACAP in peripheral tissue (such as pancreas), we performed a genetic cross between PACAP(-/-) and our recently developed transgenic mice overexpressing PACAP in pancreatic beta-cells; and then examined the survival rate of their F2 progeny. PACAP(-/-) mice were segregated into two groups based on mortality as well as body weight gain: PACAP(-/-) that survived >20 days of age with normal weight gain and PACAP(-/-) that died before 20 days with a marked weight loss. Kaplan-Meier survival analysis demonstrated that PACAP(-/-) mice and those carrying the PACAP transgene have similarly lower survival probability compared with their heterozygous littermates that served as positive controls. Further study using additional tissue-specific transgenic or knockout mouse models will be required to determine the causative defects underlying the high mortality of PACAP(-/-) mice.  相似文献   

11.
Ileo-caecal resection induced pancreatic growth in rats   总被引:1,自引:0,他引:1  
N Baba  P Chowdhury  K Inoue  M Ami  P L Rayford 《Peptides》1985,6(2):211-215
The effect of ileo-caecal resection on pancreatic growth was studied in rats four weeks after the operation. The results were compared with an identical control group who had undergone laparotomy alone. Pancreatic wet weight in ileo-caecal resectioned rats was 1.4 times greater than that found in control rats. Protein, DNA, RNA contents in the pancreas, pancreatic wet weight per 100 micrograms DNA and RNA/DNA ratio were also found significantly elevated in experimental group as opposed to the control group. Basal plasma levels of cholecystokinin (CCK) and gastrin were measured to delineate the influence of hormonal response on the pancreatic growth in ileo-caecal resected rats and were found not significantly increased after ileo-caecal resection. The data suggest that the enlargement of pancreas in ileo-caecal resected rats may be due to hyperplasia and hypertrophy of pancreatic cells; alternatively, the pancreatic growth may have been influenced by the bile acid deficiency and the reduction or release of an inhibitory factor present in the ileum of rats.  相似文献   

12.
This study was conducted to investigate the effects of a moderate dose of purified soybean agglutinin on performance and nitrogen digestibility in rats as well as to determine its effects on the protein, DNA and RNA content of the small intestine and pancreas. Twenty-four Sprague - Dawley rats were randomly allotted into one of four groups for a 10-day nitrogen balance experiment. The four groups of rats were fed 7 g of a casein-cornstarch based diet or a similar diet supplemented with 0.1, 0.2 or 0.4 mg/g purified soybean agglutinin. All experimental diets were adjusted to an identical nutrient level. Dose of soybean agglutinin had no significant effect on rat performance. Incorporation of soybean agglutinin in the diet reduced apparent protein digestibility and the utilization of dietary protein by increasing nitrogen loss from the faeces and urine. Fresh pancreatic weight increased in rats fed soybean agglutinin at a level of 0.4 mg/g in the diet compared to the control, but the dry pancreatic weight and the protein content of the pancreas did not differ among the four groups. However the DNA and RNA content of the pancreas had a tendency to increase with a higher level of soybean agglutinin. The weight of the jejunum and its protein, DNA and RNA content were not significantly affected by soybean agglutinin, but the dry weight and the RNA of the jejunum tended to increase with higher levels of soybean agglutinin in the diet. In conclusion, purified soybean agglutinin, at moderate levels in the rats diet, had negative effects on digestive function, such as nitrogen digestibility, nitrogen retention and nitrogen balance. As the level of soybean agglutinin increased, the effects became more pronounced. Meanwhile, hypertrophy of the pancreas was observed with higher doses of soybean agglutinin incorporation in the diets.  相似文献   

13.
14.
The present work reports on exocrine pancreatic secretion in control rats, adrenalectomized rats and hydrocortisone-treated (10 mg/Kg/d) rats during 7 days, under normal conditions and after induction of acute pancreatitis with caerulein (20 micrograms/Kg) by 4 subcutaneous injections at hourly intervals. Pancreatic secretion was seen to be affected by the procedure of adrenalectomy, which led to a marked reduction in the secretion of proteins and amylase with respect to control values. This was probably due to the decrease occurring in the zymogen granules in the acinar cells of the exocrine pancreas, a phenomenon which also led to a decrease in pancreatic weight observed in these animals. Treatment with hydrocortisone induced a decrease in the secretion of proteins and amylase, as well as an increase in pancreatic weight. This agrees with the accepted hypothesis that large amounts glucocorticoids stimulate the synthesis and storage of proteins in the exocrine pancreas, reducing the secretory phase. The administration of high doses of caerulein under these conditions led to acute pancreatitis in the three groups of animals. This was paralleled by a dramatic decrease in protein and amylase secretion and by severe interstitial edema of the pancreas and by increases in serum amylase values. In the case of the animals treated previously with hydrocortisone, the latter were tripled with respect to the control animals. The conclusion is offered that since the storage of enzyme proteins is governed by glucocorticoids, which furthermore increase the sensitivity of the acinar cells to stimulation by secretagogues, the administration of these substances during the development of pancreatic lesions such as acute pancreatitis is highly compromising to the organism.  相似文献   

15.
Mesenteric adipose tissue, located in the mesenterium of the intestines, is believed to play a central role in the development of obesity-related diseases. We have found that mesenteric fat samples harvested from rodents are frequently of poor quality, exhibiting partly degraded RNA. To investigate the background for this observation, we screened adipose tissue samples from two independent studies on rodents for markers of different tissues and cell types. We found that mesenteric adipose tissue samples of low quality are "contaminated" by pancreatic tissue. To locate the affected area, we dissected the mesenteric fat depots from 14 mice and measured abundance of pancreas-specific gene expression and amylase activity. As expected, we observed that the proximal section of the mesenterium, located near the pancreas, expressed pancreatic markers, whereas the distal sections did not. Approximately one-third of the mesenteric adipose tissue depots contained pancreatic tissue. Because the boundary between pancreas and mesenteric fat cannot be easily distinguished during dissection, we conclude that investigators should routinely exclude the proximal section of the mesenteric adipose tissue depot to avoid pancreatic contamination.  相似文献   

16.
ObjectivesZinc, which is found in high concentrations in the β-cells of the pancreas, is also a critical component for the endocrine functions of the pancreas. SLC30A8/ZnT8 is the carrier protein responsible for the transport of zinc from the cytoplasm to the insulin granules. The aim of this study was to investigate how dietary zinc status affects pancreatic beta cell activation and ZnT8 levels in infant male rats born to zinc-deficient mothers.MethodsThe study was performed on male pups born to mothers fed a zinc-deficient diet. A total of 40 male rats were divided into 4 equal groups. Group 1: In addition to maternal zinc deficiency, this group was fed a zinc-deficient diet. Group 2: In addition to maternal zinc deficiency, this group was fed a standard diet. Group 3: In addition to maternal zinc deficiency, this group was fed a standard diet and received additional zinc supplementation. Group 4: Control group. Pancreas ZnT8 levels were determined by ELISA method and insulin-positive cell ratios in β-cells by immunohistochemistry.ResultsThe highest pancreatic ZnT8 levels and anti-insulin positive cell ratios in the current study were obtained in Group 3 and Group 4. In our study, the lowest pancreatic ZnT8 levels were obtained in Group 1 and Group 2, and the lowest pancreatic anti-insulin positive cell ratios were obtained in Group 1.ConclusionThe results of the present study; in rats fed a zinc-deficient diet after maternal zinc deficiency has been established shows that ZnT8 levels and anti-insulin positive cell ratios in pancreatic tissue, which is significantly suppressed, reach control values with intraperitoneal zinc supplementation.  相似文献   

17.
A small yet significant increase of immunoassayable pancreatic somatostatin concentration (0.107 +/- 0.005 vs. 0.156 +/- 0.017 microgram/g at 24 hr, p less than 0.05) was found in rats, 24 hr as well as 7 days after treatment with a diabetogenic dose of streptozotocin (65 mg/kg BW). These animals were characterized by marked decreases of insulin in the pancreas without any significant changes in pancreatic glucagon concentration. These results suggest that an abrupt deprivation of insulin from islets results in an elevation of pancreatic somatostatin concentration, and that glucagon in the pancreas plays a minor role in determining pancreatic somatostatin concentration in rats with insulin-deprived diabetes of short duration.  相似文献   

18.
Induction and origin of hepatocytes in rat pancreas   总被引:10,自引:1,他引:9       下载免费PDF全文
《The Journal of cell biology》1984,98(6):2082-2090
2-[4(2,2- Dichlorocyclopropyl )phenoxy]2-methyl propionic acid (ciprofibrate), a peroxisome proliferator , induced hepatocytes in the pancreas of adult male F-344 rats when added to their diet at a dosage of 10 mg/kg body weight for 60-72 wk. These cells are morphologically indistinguishable from hepatic hepatocytes and were usually localized adjacent to islets of Langerhans with extensions into surrounding acinar tissue. A significant increase in the volume density of peroxisomes, together with immunochemically detectable amounts of two peroxisome-associated enzymes, was observed in pancreas with hepatocytes of rats maintained on ciprofibrate. Uricase-containing crystalloid nucleoids, specific for rat hepatocyte peroxisomes, were present in pancreatic hepatocytes. These structures facilitated the identification of cells with hybrid cytoplasmic features characteristic of pancreatic acinar and endocrine cells and hepatocytes. Such cells are presumed to represent a transitional state in which pancreas specific genes are being repressed while liver specific ones are simultaneously expressed. The presence of exocrine and/or endocrine secretory granules in transitional cells indicates that acinar/intermediate cells represent the precursor cell from which pancreatic hepatocytes are derived.  相似文献   

19.
Intrauterine growth restriction is a significant problem worldwide, resulting in increased rates of neonatal morbidity and mortality, as well as increased risks for metabolic and cardiovascular disease. The present study investigated the role of maternal undernutrition and l-arginine administration on fetal growth and development. Embryo transfer was utilized to generate genetically similar singleton pregnancies. On Day 35 of gestation, ewes were assigned to receive either 50 or 100% of their nutritional requirements. Ewes received i.v. injections of either saline or l-arginine three times daily from Day 100 to Day 125. Fetal growth was assessed at necropsy on Day 125. Maternal dietary manipulation altered circulating concentrations of leptin, progesterone, and amino acids in maternal plasma. Fetal weight was reduced in nutrient-restricted ewes on Day 125 compared with 100% fed ewes. Compared with saline-treated underfed ewes, maternal l-arginine administration did not affect fetal weight but increased weight of the fetal pancreas by 32% and fetal peri-renal brown adipose tissue mass by 48%. These results indicate that l-arginine administration enhanced fetal pancreatic and brown adipose tissue development. The postnatal effects of increased pancreatic and brown adipose tissue growth warrant further study.  相似文献   

20.

The metabolic syndrome (MetS) and pathologies associated with metabolic dysregulations a worldwide growing problem. Our previous study demonstrated that pioglitazone (PGZ) has beneficial effects on metabolic syndrome associated disturbances in the heart. However, mechanism mediating the molecular alterations of Ubiquitin proteasome system (UPS) and autophagy has not been investigated in rat pancreas with metabolic syndrome. For this reason, we first aimed to detect whether MetS effects on the expression of UPS (p97/VCP, SVIP, Ubiquitin) and autophagic (p62, LC3) proteins in rat pancreas. The second aim of the study was to find impact of pioglitazone on the expression of UPS and autophagic proteins in MetS rat pancreas. To answer these questions, metabolic syndrome induced rats were used as a model and treated with pioglitazone for 2 weeks. Pancreatic tissue injuries, fibrosis and lipid accumulation were evaluated histopathologically in control, MetS and MetS-PGZ groups. Apoptosis and cell proliferation of pancreatic islet cells were assessed in all groups. UPS and autophagic protein expressions of pancreas in all groups were detected by using immunohistochemistry, double-immunfluorescence and Western blotting. Compared with the controls, the rat fed with high sucrose exhibited signs of metabolic syndrome, such as higher body weight, insulin resistance, higher triglyceride level and hyperglycaemia. MetS rats showed pancreatic tissue degeneration, fibrosis and lipid accumulation when their pancreas were examined with Hematoxilen-eozin and Mallory trichrome staining. Metabolic, histopathologic parameters and cell proliferation showed greater improvement in MetS-PGZ rats and pioglitazone decreased apoptosis of islet cells. Moreover, SVIP, ubiquitin, LC3 and p62 expressions were significantly increased while only p97/VCP expression was significantly decreased in MetS-rat pancreas compared to control. PGZ treatment significantly decreased the MetS-induced increases in autophagy markers. Additionally, UPS and autophagy markers were found to colocalizated with insulin and glucagon. Colocalization ratio of UPS markers with insulin showed significant decrease in MetS rats and PGZ increased this ratio, whereas LC3-insulin colocalization displayed significant increase in MetS rats and PGZ reversed this effect. In conclusion, PGZ improved the pancreatic tissue degeneration by increasing the level of p97/VCP and decreasing autophagic proteins, SVIP and ubiquitin expressions in MetS-rats. Moreover, PGZ has an effect on the colocalization ratio of UPS and autophagy markers with insulin.

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