scholarly journals CHANGES IN PANCREATIC ACINAR CELLS DURING PROTEIN DEPRIVATION

1962 ◽  
Vol 12 (2) ◽  
pp. 313-327 ◽  
Author(s):  
Bernard Weisblum ◽  
Lawrence Herman ◽  
Patrick J. Fitzgerald
Keyword(s):  
Golgi Apparatus ◽  
Nuclear Matrix ◽  
Pancreatic Enzyme ◽  
Acinar Cells ◽  
Normal Structure ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granules ◽  
Protein Deprivation ◽  
Rat Pancreas ◽  
Protein Free Diet

After 10 days of a protein-free diet the acinar cells of the rat pancreas showed a coarsening of nuclear matrix, depletion of zymogen granules, some loss of ribosomes, and a widening of the spaces between ergastoplasmic membranes. In addition, there could be found, but rarely, a lesion of the ergastoplasm consisting of vacuoles of agranular, disoriented membranes, which was similar to a lesion produced by ethionine. Thereafter, a return toward normal structure occurred which was characterized by beginning increase in the size of the Golgi apparatus at 12 days, appearance of zymogen granules at 18 days, and a relatively normal appearing but smaller cell at 28 days. After 10 to 12 days of protein deprivation a reversal of many of the morphologic effects of protein deprivation was accompanied by a return toward normal of some pancreatic enzyme activities. Possibly this spontaneous return toward normal levels represented a raiding of protein stores, or it may have been an adaptive phenomenon.

Sorafenib-induced loss of polarity of zymogen granules in pancreatic acinar cells.

2012 ◽  
Vol 30 (4_suppl) ◽  
pp. 236-236
Author(s):  
Tatsuo Ito ◽  
Ryuichiro Doi ◽  
Shinji Uemoto
Keyword(s):  
Acute Pancreatitis ◽  
Kinase Inhibitor ◽  
Pancreatic Enzyme ◽  
Acinar Cells ◽  
In Vivo Studies ◽  
Pancreatic Acinar Cells ◽  
Control Group ◽  
Amylase Level ◽  
Zymogen Granules ◽  
Tissue Samples

236 Background: Sorafenib is an oral multi-kinase inhibitor which is regarded as a key drug for HCC and RCC. It has been unexpectedly found that the compound causes an increase of serum pancreatic enzyme levels without clinically recognized pancreatitis. The reason for this event is not well understood yet. The aim of this study was to clarify the mechanisms involved in this phenomenon. Methods: Eight-week old BALB/cA male mice were used in in vivo studies. Sorafenib tosylate was administered per os once daily at a dose of 150 mg/kg body weight. Control mice were given vehicle alone. Mice were sacrificed 24 hr after 1-, 2-, 3- and 7-day administration of the compound, and blood samples and pancreatic tissue samples were obtained (n=5 for each group). The tissue samples were used for hematoxylin and eosin (HE) staining, immunohistochemistry, electron microscopy (EM), western blot and RT-quantitative PCR studies. Results: Serum amylase levels were elevated after sorafenib administration. The amylase level hit the peak after 2-day administration, and then gradually decreased. By HE staining, the control group without sorafenib showed a basophilic stained area in the baso-lateral site of the acinar cells. In contrast, the acinar cytoplasm after 2-day administration of sorafenib was totally eosinophilic. The typical findings of acute pancreatitis were not seen in the both group. By EM examination, zymogen granules (ZGs) of the sorafenib group spread into basal site of the acinar cells. ZGs mounted up on both of apical and baso-lateral plasma membrane and showed exocytosis. The levels of amylase mRNA were not elevated by sorafenib. In addition the expression of N-ethylmaleimidesensitive factor attachment protein receptor (SNARE) proteins was not changed. Conclusions: The results suggest that the amount of acinar amylase production was not changed but the distribution of ZGs was altered by sorafenib. Sorafenib seemed to cause temporary loss of polarity of ZGs secretion in acinar cells by blocking apical exocytosis. Acute pancreatitis was not evident; thus the current model was not similar to the pancreatitis model caused by the supra-maximal secretagogue stimulation which blocks the apical exocytosis.

A novel zymogen granule protein (ZG29p) and the nuclear protein MTA1p are differentially expressed by alternative transcription initiation in pancreatic acinar cells of the rat

1999 ◽  
Vol 112 (15) ◽  
pp. 2539-2548
Author(s):  
R. Kleene ◽  
J. Zdzieblo ◽  
K. Wege ◽  
H.F. Kern
Keyword(s):  
Blot Analysis ◽  
Transcription Initiation ◽  
Northern Blot Analysis ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granule ◽  
Zymogen Granules ◽  
Rt Pcr ◽  
Rat Pancreas ◽  
Alternative Transcription

Using a polyclonal antibody against purified zymogen granule membrane components from rat pancreas a cDNA coding for the 29 kDa protein (ZG29p) was identified by immunoscreening of a hormonally stimulated pancreas cDNA library. Western blot analysis suggests that ZG29p is a pancreas-specific protein and immunofluorescence shows that ZG29p is mainly associated with zymogen granules. Analysis of subcellular fraction applying immunoblotting revealed that ZG29p was localized mainly in the soluble fraction of zymogen granules and in a Golgi- and RER-enriched fraction, but was absent from the cytosol. In isolated zymogen granule content ZG29p was associated with protein complexes containing amylase as main constituent. The cDNA coding for ZG29p is homologous to the C-terminal region of the candidate metastasis-associated gene mta1. Northern blot analysis and RT-PCR showed that no MTA1 mRNA is present in pancreas from fasted rats and in the rat pancreas carcinoma cell line AR4-2J in its protodifferentiated state. Although no ZG29p specific mRNA was seen in the northern blot analysis, RT-PCR showed that ZG29p was expressed under both non-stimulated and stimulated conditions. The expression of MTA1 was up-regulated in the pancreas by endogenous cholecystokinin release and in AR4-2J after induction of cellular differentiation by dexamethasone. Western blotting and immunofluorescense studies indicated that MTA1p is localized in the nucleus in all tissues studied. Using genomic DNA in PCR analysis it was shown that two short introns are present flanking the sequences of the 5′end of ZG29p cDNA. One intron contains consensus elements required for pancreas specific transcription initiation, suggesting that MTA1 and ZG29 are differentially expressed by alternative transcription initiation in the pancreas. The localisation of MTA1p in the nucleus of most cell types could signify a general role in gene regulation, while the cell type specific and exclusive expression of ZG29p in pancreatic acinar cells could indicate a role in granule formation.

Regulation of cytosolic free Ca2+ concentration in acinar cells of rat pancreas

1983 ◽  
Vol 245 (3) ◽  
pp. G347-G357 ◽  
Author(s):  
H. Streb ◽  
I. Schulz
Keyword(s):  
Steady State ◽  
Incubation Medium ◽  
Minimal Medium ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Atpase Inhibitor ◽  
Rat Pancreas ◽  
Mitochondrial Inhibitors ◽  
Pancreatic Cells ◽  
State Concentration

Ca2+ uptake into isolated exocrine pancreatic cells with highly permeable plasma membrane was determined by measuring the decrease in free Ca2+ concentration of the surrounding incubation medium with a Ca2+-specific electrode. In the presence of Mg-ATP and respiratory substrates the free Ca2+ concentration of the incubation medium decreased rapidly after addition of leaky cells until a stable medium free Ca2+ concentration of 4.2 +/- 0.1 X 10(-7) mol/l was obtained. Changes in the medium free Ca2+ concentration at steady state by addition of Ca2+ or EGTA were buffered by cellular uptake or release, respectively, until the steady-state free Ca2+ concentration was reestablished. When nonmitochondrial Ca2+ uptake was determined in the presence of a combination of mitochondrial inhibitors (10(-5) mol/l antimycin, 5 X 10(-6) mol/l oligomycin, and 10(-2) mol/l azide), the rate of uptake was considerably reduced, while the steady-state concentration was unaltered. In contrast, mitochondrial uptake that could be observed in the presence of the ATPase inhibitor vanadate (2 X 10(-3) mol/l) proceeded at the same rate as the control, but the minimal medium free Ca2+ concentration reached was 2.4 +/- 0.1 X 10(-7) mol/l higher than the control. Addition of secretagogues at steady-state free Ca2+ concentration resulted in a Ca2+ release of 0.73 +/- 0.08 nmol/mg protein. The increase in medium free Ca2+ concentration was entirely transient and followed by reuptake to the prestimulation level. The data indicate that a cytosolic free Ca2+ concentration of 4 X 10(-7) mol/l can be regulated in pancreatic acinar cells by a nonmitochondrial Mg2+-dependent Ca2+ pool.

scholarly journals SYNTHESIS AND MIGRATION OF PROTEINS IN THE CELLS OF THE EXOCRINE PANCREAS AS REVEALED BY SPECIFIC ACTIVITY DETERMINATION FROM RADIOAUTOGRAPHS

1963 ◽  
Vol 16 (1) ◽  
pp. 1-23 ◽  
Author(s):  
H. Warshawsky ◽  
C. P. Leblond ◽  
B. Droz
Keyword(s):  
Specific Activity ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granule ◽  
Zymogen Granules ◽  
The Mean ◽  
And Migration ◽  
Rats And Mice ◽  
Silver Grains ◽  
Golgi Zone

Radioautographs of pancreatic acinar cells were prepared in rats and mice sacrificed at various times after injection of leucine-, glycine-, or methionine-H3. Measurements of radioactivity concentration (number of silver grains per unit area) and relative protein concentration (by microspectrophotometry of Millon-treated sections) yielded the mean specific activity of proteins in various regions of the acinar cells. The 2 to 5 minute radioautographs as well as the specific activity time curves demonstrate protein synthesis in ergastoplasm. From there, most newly synthesized proteins migrate to and accumulate in the Golgi zone. Then they spread to the whole zymogen region and, finally, enter the excretory ducts. An attempt at estimating turnover times indicated that two classes of proteins are synthesized in the ergastoplasm: "sedentary" with a slow turnover (62.5 hours) and "exportable" with rapid turnover (4.7 minutes). It is estimated that the exportable proteins spend approximately 11.7 minutes in the Golgi zone where they are built up into zymogen granules, and thereafter 36.0 minutes as fully formed zymogen granules, before they are released outside the acinar cell as pancreatic secretion. The mean life span of a zymogen granule in the cell is estimated to be 47.7 minutes.

scholarly journals Double immunocytochemical labeling applying the protein A-gold technique.

1982 ◽  
Vol 30 (1) ◽  
pp. 81-85 ◽  
Author(s):  
M Bendayan
Keyword(s):  
Tissue Section ◽  
Protein A ◽  
Antigenic Site ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Secretory Proteins ◽  
Zymogen Granules ◽  
Double Labeling ◽  
Gold Particles ◽  
Antigenic Sites

In the present study we report the modifications and the different steps of the protein A-gold (pAg) technique that allow the simultaneous demonstration of two antigenic sites on the same tissue section. The labeling is carried out in the following manner: face A of the tissue section is incubated with an antiserum followed by a pAg complex prepared with large gold particles; face B of the same tissue section is then incubated with a second antiserum followed by a pAg complex prepared with small gold particles. Each of the pAg complexes reveals a different antigenic site on opposite faces of the tissue section. The transparency of the section in the electron beam allows the visualization of the gold particles present on both faces. The double labeling pAg technique was applied for the simultaneous demonstration of two secretory proteins in the same Golgi, condensing vacuoles, and zymogen granules of the rat pancreatic acinar cells.

scholarly journals The effect of fasting on enzyme levels in the enlarged and involuting rat pancreas

1987 ◽  
Vol 58 (3) ◽  
pp. 427-436 ◽  
Author(s):  
R. A. Crass ◽  
P. S. Oatesa ◽  
R. G. H. Morgan
Keyword(s):  
Trypsin Inhibitor ◽  
Digestive Enzyme ◽  
Pancreatic Enzyme ◽  
Soya Bean ◽  
High Rate ◽  
Pancreatic Acinar Cells ◽  
Zymogen Granules ◽  
Triacylglycerol Lipase ◽  
Intracellular Enzyme ◽  
Bean Flour

1. The effect on pancreatic digestive enzyme levels of fasting and changes from a diet containing trypsin inhibitor (raw soya-bean flour, RSF) to diets free of trypsin inhibitor (heated soya-bean flour, HSF, or commercial rat chow) was studied in rats for up to 7 d.2. In RSF-fed rats killed without fasting, enzyme levels were low, but after fasting for 24 h before killing there was a marked increase in all enzyme levels. Histological studies showed that pancreatic acinar cells from RSF-fed rats killed without fasting were devoid of zymogen granules, but following a 24 h fast there was a marked accumulation of zymogen granules which extend into the basal cytoplasm. Fasting either produced no change or a fall in enzyme levels in rats fasted after feeding HSF or chow continuously.3. If animals fed on RSF were changed to HSF and either fed or fasted for 24 h up to the time of killing there was an increase in amylase (EC3. 2. 1. 1), trypsin (EC3. 4. 21. 4), lipase (triacylglycerol lipase;EC3. 1. 1. 3) and protein 1 d after the change, followed by a fall over the next 6 d to levels similar to those seen in rats fed on HSF continuously.4. Animals changed from RSF to chow showed similar effects as far as trypsin, lipase and protein were concerned, but amylase rose, to reach the level seen in rats fed on chow continuously (about ten times that seen in soya-bean-fed rats), after 2 d.5. These results suggest that in the rats fed on RSF, pancreatic enzyme synthesis is rapid but secretion is equally rapid and intracellular enzyme levels are low. When these animals are fasted or changed to a diet free of trypsin inhibitor the rate of secretion falls but the high rate of synthesis continues for at least 24 h and enzymes accumulate in the pancreas. In studies of pancreatic enzyme levels in rats fed on trypsin inhibitor the extent of fasting before killing the animal is therefore an important variable. Such animals should probably not be fasted before study.

scholarly journals The cytochemical localization of adenylate cyclase: fact or artifact?

1978 ◽  
Vol 26 (4) ◽  
pp. 298-312 ◽  
Author(s):  
H J Kempen ◽  
J J de Pont ◽  
S L Bonting ◽  
A M Stadhouders
Keyword(s):  
Particulate Matter ◽  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Lead Nitrate ◽  
Acinar Cells ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Pancreatic Acinar Cells ◽  
Rat Pancreas ◽  
Isolated Rat

In a study of the location of adenylate cyclase activity in rat pancreas with the method of Reik et al. (Science 168:382, 1970), as modified by Howell and Whitfield (J Histochem Cytochem 20:873, 1972) it was found that (a) unspecific staining occurs in rat pancreatic tissue fragments incubated in the Reik-Howell medium in the absence of substrate; (b) addition of adenylyl-imidodiphosphate (AMP-PNP) as substrate, either alone or together with stimulants of rat pancreas adenylate cyclase (secretin. NaF), does not result in increased precipitation; (c) cytochemical incubation of isolated rat pancreatic acinar cells and of rat liver and kidney fragments does not lead to substrate-specific precipitation. In subsequent chemical studies we have found that cyclic adenosine monophosphate (AMP) formation from [alpha32P]AMP-PNP in the presence of rat pancreatic particulate matter is very low in the Reik-Howell medium without lead ions, but is stimulated by addition of lead nitrate (4 mM). Whereas heat-treatment of the particulate matter abolishes all cyclic AMP formation in the absence of lead ions, it actually increases cyclic AMP production in the presence of 4 mM lead nitrate. This indicates that the cyclic AMP formation in the complet Reik-Howell medium occurs by a nonenzymatic mechanism. In addition, this medium shows a tendency to become turbid, particularly when calcium ions are added to the medium, suggesting a possible explanation for the apparently specific cytochemical detection observed by other authors. A revised cytochemical medium, with barium replacing lead and with a pH of 8.9 (optimal for adenylate cyclase with AMP-PNP substrate), leaves rat pancreatic adenylate cyclase activity intact and hormone sensitive, while it is still able to precipitate imidodiphosphate. However, cytochemical incubation of isolated rat pancreatic acinar cells in this revised medium in the presence of AMP-PNP and secretin does not yield an electron-dense precipitate, showing that the enzyme activity is to low to produce sufficient imidodiphosphate. These findings throw further doubt on the validity of the cytochemical detection of adenylate cyclase, reported by other investigators, notwithstanding the alleged positive results.

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