scholarly journals Quantitative immunocytochemical localization of pancreatic secretory proteins in subcellular compartments of the rat acinar cell.

1980 ◽  
Vol 28 (2) ◽  
pp. 149-160 ◽  
Author(s):  
M Bendayan ◽  
J Roth ◽  
A Perrelet ◽  
L Orci

The recently developed protein A-gold technique for the detection of intracellular antigenic sites on thin sections was utilized to localize nine different secretory proteins in the rat exocrine pancreas. Amylase, chymotrypsinogen, trypsinogen, lipase, elastase, carboxypeptidases A and B, RNase and DNase, were detected at the level of the rough endoplasmic reticulum, the Golgi area, and the zymogen granules of the acinar cells, as well as in the acinar lumen. A quantitative evaluation of the labeling showed that its intensity was not identical for all enzymes studied nor in all cellular compartments analyzed. An increasing gradient of the labeling from the rough endoplasmic reticulum to the Golgi and to the zymogen granules was found for amylase, carboxypeptidases A and B, chymotrypsinogen, trypsinogen, and RNase, while a comparable low degree of labeling in the Golgi apparatus and in the zymogen granules was observed for DNase, lipase, and elastase. These results suggest that the nine enzymes are processed through the same intracellular compartments, but that they may be concentrated to different degrees in the zymogen granules before being released in the acinar lumen.

1982 ◽  
Vol 30 (1) ◽  
pp. 58-66 ◽  
Author(s):  
M Bendayan ◽  
T B Orstavik

The subcellular localization of kallikrein was studied in the rat pancreas using the immunocytochemical protein A-gold technique. Kallikrein was found at the level of the rough endoplasmic reticulum (RER), Golgi cisternae, condensing vacuoles, and zymogen granules of the pancreatic acinar cells as well as in the acinar lumen. The effect of various tissue processings on the immunocytochemical labeling of kallikrein was evaluated using pancreatic tissue fixed in glutaraldehyde and embedded in Epon, Lowicryl K4M, or glycol methacrylate (GMA). Compared to the results obtained with Epon, Lowicryl allowed improved resolution and specificity in the immunocytochemical labeling, while GMA retained greater amounts of kallikrein antigenicity leading to a higher intensity in the labeling; since it also gave a good ultrastructural preservation, GMA appeared to be the superior embedding medium for the localization of kallikrein. The quantitative evaluation of the labeling obtained under the three embedding conditions showed the presence of an increasing concentration gradient along the RER-Golgi-granule secretory pathway, suggesting that, like other pancreatic exocrine enzymes, kallikrein is synthesized in the RER, processed through the Golgi apparatus, and packed in the zymogen granules before being released into the acinar lumen.


1984 ◽  
Vol 98 (2) ◽  
pp. 399-406 ◽  
Author(s):  
J Roth

The O-linked oligosaccharides of mucin-type glycoproteins contain N-acetyl-D-galactosamine (GalNAc) that is not found in N-linked glycoproteins. Because Helix pomatia lectin interacts with terminal GalNAc, we used this lectin, bound to particles of colloidal gold, to localize such sugar residues in subcellular compartments of intestinal goblet cells. When thin sections of low temperature Lowicryl K4M embedded duodenum or colon were incubated with Helix pomatia lectin-gold complexes, no labeling could be detected over the cisternal space of the nuclear envelope and the rough endoplasmic reticulum. A uniform labeling was observed over the first and several subsequent cis Golgi cisternae and over the last (duodenal goblet cells) or the two last (colonic goblet cells) trans Golgi cisternae as well as forming and mature mucin droplets. However, essentially no labeling was detected over several cisternae in the central (medial) region of the Golgi apparatus. The results strongly suggest that core O-glycosylation takes place in cis Golgi cisternae but not in the rough endoplasmic reticulum. The heterogenous labeling for GalNAc residues in the Golgi apparatus is taken as evidence that termination of certain O-oligosaccharide chains by GalNAc occurs in trans Golgi cisternae.


1985 ◽  
Vol 33 (4) ◽  
pp. 323-332 ◽  
Author(s):  
J Lacasse ◽  
M Ballak ◽  
C Mercure ◽  
J Gutkowska ◽  
C Chapeau ◽  
...  

The involvement of various organelles in the synthesis, transport, and packaging of renin in the juxtaglomerular cells of newborn mice has been investigated by immunocytochemistry with the protein A-gold technique. Highly specific rabbit antibodies against mouse submandibular renin were used. Mild fixation and embedding in glycol methacrylate allowed enough sensitivity to identify a steep gradient of labeling from rough endoplasmic reticulum to Golgi complex to secretory granules. Routine fixation and embedding in Epon produced labeling differentials that allowed delineation of hitherto ill-defined types of secretory granules and vacuoles. The classical pattern of synthesis, transport, and packaging of secretory proteins involves the rough endoplasmic reticulum and Golgi complex and seems to apply to renin secretion. Immunoreactive renin is packaged as rhomboid crystals at the trans face of the Golgi complex. The limiting membrane of these rhomboids fuses to form coalescing protogranules where the crystals eventually yield their individuality maturing into secretory granules. Vacuoles containing a flocculent material, with or without a dense core, show significant immunocytochemical labeling. These vacuoles are not associated with the Golgi complex but occupy cytoplasmic areas well endowed with rough endoplasmic reticulum. As judged from their morphological features and their immunoreactivity, the vacuoles do not seem to follow the sequence of events typical of protogranules and coalescing protogranules. They possibly represent a parallel pathway of renin synthesis and transport, involving the nuclear envelope and bypassing the Golgi complex.


1982 ◽  
Vol 30 (1) ◽  
pp. 81-85 ◽  
Author(s):  
M Bendayan

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.


1991 ◽  
Vol 69 (11) ◽  
pp. 2574-2577 ◽  
Author(s):  
Hari B. Krishnan ◽  
Jerry A. White ◽  
Steven G. Pueppke

Antibodies raised against gliadins, the alcohol-soluble proteins of wheat (Triticum aestivum L.) seeds, were used to localize gliadins within the lumen of the endoplasmic reticulum. Endosperm cells at 20 days after anthesis contain extensive rough endoplasmic reticulum that is fragmented and dilated. The dilated endoplasmic reticulum encloses aggregates of proteinaceous material that reacts strongly with gliadin-specific antibodies. Key words: gliadins, immunocytochemistry, protein A – gold, rough endoplasmic reticulum, wheat.


1964 ◽  
Vol 20 (3) ◽  
pp. 473-495 ◽  
Author(s):  
Lucien G. Caro ◽  
George E. Palade

The synthesis, intracellular transport, storage, and discharge of secretory proteins in and from the pancreatic exocrine cell of the guinea pig were studied by light- and electron microscopical autoradiography using DL-leucine-4,5-H3 as label. Control experiments were carried out to determine: (a) the length of the label pulse in the blood and tissue after intravenous injections of leucine-H3; (b) the amount and nature of label lost during tissue fixation, dehydration, and embedding. The results indicate that leucine-H3 can be used as a label for newly synthesized secretory proteins and as a tracer for their intracellular movements. The autoradiographic observations show that, at ∼5 minutes after injection, the label is localized mostly in cell regions occupied by rough surfaced elements of the endoplasmic reticulum; at ∼20 minutes, it appears in elements of the Golgi complex; and after 1 hour, in zymogen granules. The evidence conclusively shows that the zymogen granules are formed in the Golgi region by a progressive concentration of secretory products within large condensing vacuoles. The findings are compatible with an early transfer of label from the rough surfaced endoplasmic reticulum to the Golgi complex, and suggest the existence of two distinct steps in the transit of secretory proteins through the latter. The first is connected with small, smooth surfaced vesicles situated at the periphery of the complex, and the second with centrally located condensing vacuoles.


1987 ◽  
Vol 66 (2) ◽  
pp. 412-419 ◽  
Author(s):  
A.R. Hand ◽  
R. Coleman ◽  
M.R. Mazariegos ◽  
J. Lustmann ◽  
L.V. Lotti

The ability of the intralobular duct cells of the rat parotid gland to take up protein from the lumen was examined by retrograde infusion of exogenous proteins and by immunogold localization of endogenous secretory proteins. Small amounts of native horseradish peroxidase (HRP) were taken up by intercalated and striated duct cells, and were present in small vesicles, multi vesicular bodies, and lysosomes. In contrast, HRP modified by periodate oxidation was avidly internalized by the duct cells and was present in large apical vacuoles that acquired lysosomal hydrolase activity. Native and cationized ferritin were taken up in a similar manner when infused at a high concentration (up to 10 mg/mL). At lower concentrations (0.3-1.0 mg/mL), endocytosis of cationized ferritin occurred mainly in small apical tubules and vesicles in striated duct cells. Little native ferritin was taken up at these concentrations. After stimulation of acinar cell secretion by isoproterenol, similar vacuoles were occasionally observed in both intercalated and striated duct cells. Labeling of thin sections with antibodies to amylase and to a 26,000-dalton secretory protein (protein B1), followed by protein A-gold, revealed the presence of these proteins in the vacuoles, indicating endocytosis of acinar secretory proteins by the duct cells. Although uptake of acinar proteins by duct cells occurs at a low rate in normal animals, previous work suggests that extensive endocytosis may occur in certain pathological conditions. This may be a mechanism for removing abnormal or modified proteins from saliva before it reaches the oral cavity.


1986 ◽  
Vol 34 (2) ◽  
pp. 203-207 ◽  
Author(s):  
G Posthuma ◽  
J W Slot ◽  
H J Geuze

Malaisse-Lagae demonstrated in 1975 that peri-insular (PI) cells and tele-insular (TI) cells produce amylase (Am) and chymotrypsinogen (Ch) in a different ratio. These biochemical measurements are in contradiction with recent observations of Bendayan (1985), who found that the Am/Ch ratio measured with the protein A-gold technique applied to ultrathin Epon sections was the same in PI and TI cells. We have previously shown (Posthuma et al., 1984) that experimentally induced changes in Am and Ch content of rat pancreas are quantitatively reflected by immuno-gold labeling of zymogen granules in cryosections. Here we applied the same technique to compare the Am/Ch labeling density ratios in PI and TI pancreatic cells. To ascertain constancy of experimental conditions, we used ultrathin cryosections from tissue blocks consisting of TI and PI tissue elements. Consecutive sections of these blocks were alternatively immunolabeled for Am and Ch, using protein A-gold as marker. The density of gold particles over zymogen granules of both PI and TI cells was measured. It appeared that the Am/Ch labeling density ratio was significantly lower in PI than in TI cells. This difference resulted from a lower Am labeling as well as higher Ch labeling density over zymogen granules in PI cells.


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