Secretion of protein by the acinar cells of the rat pancreas, as studied by electron microscopic radioautography

1964 ◽  
Vol 148 (3) ◽  
pp. 485-497 ◽  
Author(s):  
Huberta E. Van Heyningen
Keyword(s):  
Acinar Cells ◽  
Electron Microscopic ◽  
Rat Pancreas ◽  
Electron Microscopic Radioautography

A simplified method of emulsion coating and development for quantitative electron microscopic radioautography

1978 ◽  
Vol 36 (2) ◽  
pp. 64-65
Author(s):  
K. Yoshida ◽  
F. Murata ◽  
S. Ohno ◽  
T. Nagata
Keyword(s):  
Mass Production ◽  
Identical Condition ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Simplified Method ◽  
Complicated Process ◽  
Critical Problems ◽  
Electron Microscopic Radioautography ◽  
Quantitative Radioautography

IntroductionSeveral methods of mounting emulsion for radioautography at the electron microscopic level have been reported. From the viewpoint of quantitative radioautography, however, there are many critical problems in the procedure to produce radioautographs. For example, it is necessary to apply and develop emulsions in several experimental groups under an identical condition. Moreover, it is necessary to treat a lot of grids at the same time in the dark room for statistical analysis. Since the complicated process and technical difficulties in these procedures are inadequate to conduct a quantitative analysis of many radioautographs at once, many factors may bring about unexpected results. In order to improve these complicated procedures, a simplified dropping method for mass production of radioautographs under an identical condition was previously reported. However, this procedure was not completely satisfactory from the viewpoint of emulsion homogeneity. This paper reports another improved procedure employing wire loops.

Platelet Incorporation of Labelled Adenosine and Adenosine Diphosphate

1969 ◽  
Vol 22 (02) ◽  
pp. 304-315 ◽  
Author(s):  
E. W Salzman ◽  
T. P Ashford ◽  
D. A Chambers ◽  
Lena L. Neri
Keyword(s):  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Platelet Inhibition ◽  
Electron Microscopic ◽  
Platelet Binding ◽  
Minor Degree ◽  
A Minor ◽  
Plasma Marker ◽  
Electron Microscopic Radioautography ◽  
Simultaneous Assessment

SummaryAfter incubation of platelet-rich plasma with labelled adenosine or ADP, platelet incorporation of radioactivity was assessed. Platelets were rapidly separated for counting by filtration through cellulose acetate Millipore. Inulin-H3 served as a plasma marker, and triple isotope techniques permitted simultaneous assessment of the behavior of the adenine and phosphate moieties of ADP without washing of platelets. In other experiments, electron microscopic radioautography was employed to trace the label after platelet incorporation.The results were consistent with previous reports that ADP is dephosphorylated in plasma and is incorporated by platelets only as a dephosphorylated residue, probably adenosine. The label crossed the platelet membrane and entered the platelet, where it was distributed in platelet granules and the agranular cell sap. Concentration within granules occurred to a minor degree.The results support the hypothesis that platelet aggregation by ADP occurs without a persistent bond of ADP to the platelet. Inhibition of aggregation by adenosine probably depends on a metabolic or transport process rather than on competition between adenosine and ADP for platelet binding sites.

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 Electron Microscopic Radioautographic Study on Protein Synthesis in Mitochondria of Binucleate Hepatocytes of Aging Mice

2007 ◽  
Vol 7 ◽  
pp. 1008-1023 ◽  
Author(s):  
Tetsuji Nagata
Keyword(s):  
Protein Synthesis ◽  
Labeling Index ◽  
Electron Microscopic ◽  
Protein Precursor ◽  
Binucleate Cells ◽  
Mouse Hepatocytes ◽  
Electron Microscopic Radioautography ◽  
Liver Tissues

In order to study the aging changes of intramitochondrial protein synthesis in mouse hepatocytes, 10 groups of aging mice, each consisting of three individuals, total 30, from fetal day 19 to postnatal year 2, were injected with3H-leucine, a protein precursor, sacrificed 1 h later, and the liver tissues processed for electron microscopic radioautography. On electron microscopic radioautograms obtained from each animal, the numbers of mitochondria, the numbers of labeled mitochondria, and the mitochondrial labeling index labeled with3H-leucine that showed protein synthesis in each hepatocyte, both mononucleate and binucleate cells, were counted and the averages in respective aging groups were compared. From the results, it was demonstrated that the numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein syntheses in both mononucleate and binucleate hepatocytes of mice at various ages increased due to development of animals. The numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein synthesis in binucleate hepatocytes were more than those of mononucleate hepatocytes at the same aging stages.

Potassium transport across basolateral membrane of acinar cells in the perfused rat pancreas

1991 ◽  
Vol 261 (4) ◽  
pp. G570-G577
Author(s):  
T. Ishikawa ◽  
T. Kanno
Keyword(s):  
Basolateral Membrane ◽  
Acinar Cells ◽  
Fluid Secretion ◽  
Potassium Transport ◽  
Perfused Rat Pancreas ◽  
Complete Replacement ◽  
Rat Pancreas ◽  
Initial Transient ◽  
K Concentration ◽  
K Transport

Efflux and influx of K+ across the basolateral membrane of acinar cells were continuously computed from the change in K+ concentration in the perfusate collected from the portal vein of the isolated perfused rat pancreas. Continuous stimulation with different concentrations of COOH-terminal octapeptide of cholecystokinin (CCK-8) caused characteristic patterns of K+ flux and fluid secretion as follows: 1) stimulation with 10 pM CCK-8 induced a gradual and small increase in K+ influx and sustained fluid secretion; 2) stimulation with 100 pM CCK-8 caused an initial transient K+ efflux followed by a secondary slow K+ influx and sustained fluid secretion; 3) stimulation with 1 nM CCK-8 also induced an initial transient K+ efflux followed by a secondary slow K+ influx, whereas there was only a slight transient increase in fluid secretion. Ouabain abolished the CCK-8-induced K+ influx, but furosemide had little, if any, effect on the CCK-8-induced K+ flux and fluid secretion. Complete replacement of Cl- with equimolar NO3- had little effect on the CCK-8-induced K+ influx. These results suggest that CCK-8 activates not only passive K+ transport but also an ouabain sensitive Na(+)-K+ pump and that the furosemide-sensitive Na(+)-K(+)-2Cl- symport may not play a significant role in CCK-8-induced K+ transport.

scholarly journals Receptor-mediated entry of beta-glucuronidase into the parasitophorous vacuoles of macrophages infected with Leishmania mexicana amazonensis.

1983 ◽  
Vol 157 (5) ◽  
pp. 1471-1482 ◽  
Author(s):  
V L Shepherd ◽  
P D Stahl ◽  
P Bernd ◽  
M Rabinovitch
Keyword(s):  
Bone Marrow ◽  
Half Life ◽  
Mannose Receptor ◽  
Leishmania Mexicana ◽  
Preputial Gland ◽  
Electron Microscopic ◽  
Infected Cells ◽  
Secondary Lysosomes ◽  
Electron Microscopic Radioautography

125I-labeled rat preputial gland beta-glucuronidase was shown by light and electron microscopic radioautography to accumulate within the parasitophorous vacuoles of in vitro derived bone marrow macrophages infected with Leishmania mexicana amazonensis. beta-glucuronidase uptake was mediated by the mannose receptor, since the penetration of the ligand was inhibited by mannan. Uptake was detected as soon as 4 h after incubation of infected cells with the ligand, and increased at 24 and 48 h. The label persisted in the vacuoles for at least 24 h after a 24-h pulse with the ligand, a finding compatible with the relatively long half-life of labeled beta-glucuronidase in normal macrophages. Parasitophorous vacuoles were also labeled in macrophages exposed to the ligand only before infection, indicating that secondary lysosomes containing the ligand fused with the parasitophorous vacuoles. Another mannosylated ligand, mannose-BSA, which, in contrast to beta-glucuronidase, is rapidly degraded in macrophage lysosomes, did not detectably accumulate in the vacuoles. The results support and extend information previously obtained with electron opaque tracers that emphasizes the phagolysosomal nature of Leishmania parasitophorous vacuoles. In addition, the results suggest that appropriate mannosylated molecules may be used as carriers for targeting of leishmanicidal drugs to the parasitophorous vacuoles of infected macrophages.

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