scholarly journals Studies on the secretory process in exocrine pancreas cells. II. C57 black and beige mice.

1978 ◽  
Vol 26 (2) ◽  
pp. 83-93 ◽  
Author(s):  
A B Novikoff ◽  
N Quintana ◽  
M Mori
Keyword(s):  
Acid Phosphatase ◽  
Exocrine Pancreas ◽  
Secretory Granules ◽  
Pancreatic Acinar Cells ◽  
Secretory Process ◽  
Residual Body ◽  
Body Type ◽  
Electron Microscopic ◽  
Black Mouse ◽  
Pancreatic Exocrine

Published electron microscopic and cytochemical studies (thiamine pyrophosphatase and acid phosphatase) on exocrine pancreas cells of guinea pig, hamster, rat and rabbit have demonstrated that the nascent secretory granules, or condensing vacuoles, are part of GERL. The studies reported here show this to be true of the mouse pancreatic exocrine cells as well, thus permitting comparison of this cell type in the C57 black mouse and its "beige" mutant. This is of considerable interest because GERL is very much enlarged in these cells of the beige mouse. Most of GERL consists of wide dilated portions filled with electron-opaque materials that appear to be packaged into huge residual body-type lysosomes ("anomalous granules"). Acid phosphatase activity is demonstrable not only in these portions of GERL, but also in the condensing vacuoles as in pancreatic acinar cells in the black mouse where these dilated lysosome-producing regions are not present.

scholarly journals LYSOSOME FUNCTION IN THE REGULATION OF THE SECRETORY PROCESS IN CELLS OF THE ANTERIOR PITUITARY GLAND

1966 ◽  
Vol 31 (2) ◽  
pp. 319-347 ◽  
Author(s):  
Robert E. Smith ◽  
Marilyn G. Farquhar
Keyword(s):  
Anterior Pituitary ◽  
Dense Body ◽  
Secretory Granules ◽  
Secretory Process ◽  
Secretory Cells ◽  
Residual Body ◽  
Multivesicular Bodies ◽  
Dense Bodies ◽  
Pituitary Glands ◽  
Secretory Products

The nature and content of lytic bodies and the localization of acid phosphatase (AcPase) activity were investigated in mammotrophic hormone-producing cells (MT) from rat anterior pituitary glands. MT were examined from lactating rats in which secretion of MTH1 was high and from postlactating rats in which MTH secretion was suppressed by removing the suckling young. MT from lactating animals contained abundant stacks of rough-surfaced ER, a large Golgi complex with many forming secretory granules, and a few lytic bodies, primarily multivesicular bodies and dense bodies. MT from postlactating animals, sacrificed at selected intervals up to 96 hr after separation from their suckling young, showed (a) progressive involution of the protein synthetic apparatus with sequestration of ER and ribosomes in autophagic vacuoles, and (b) incorporation of secretory granules into multivesicular and dense bodies. The content of mature granules typically was incorporated into dense bodies whereas that of immature granules found its way preferentially into multivesicular bodies. The secretory granules and cytoplasmic constituents segregated within lytic bodies were progressively degraded over a period of 24 to 72 hr to yield a common residual body, the vacuolated dense body. In MT from lactating animals, AcPase reaction product was found in lytic bodies, and in several other sites not usually considered to be lysosomal in nature, i.e., inner Golgi cisterna and associated vesicles, and around most of the immature, and some of the mature secretory granules. In MT from postlactating animals, AcPase was concentrated in lytic bodies; reaction product and incorporated secretory granules were frequently recognizable within the same multivesicular or dense body which could therefore be identified as "autolysosomes" connected with the digestion of endogenous materials. Several possible explanations for the occurrence of AcPase in nonlysosomal sites are discussed. From the findings it is concluded that, in secretory cells, lysosomes function in the regulation of the secretory process by providing a mechanism which takes care of overproduction of secretory products.

scholarly journals CYTOLOGICAL STUDIES ON TWO FUNCTIONAL HEPATOMAS

1962 ◽  
Vol 15 (2) ◽  
pp. 289-312 ◽  
Author(s):  
Edward Essner ◽  
Alex B. Novikoff
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Golgi Apparatus ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Secretory Granules ◽  
Dynamic State ◽  
Secretory Product ◽  
Electron Microscopic ◽  
Golgi Membranes

The Reuber hepatoma H-35 and Morris hepatoma 5123 have been studied by electron microscopy and by cytochemical staining methods for a number of phosphatases. These studies emphasize the resemblances of the two tumors to rat liver, but they also indicate distinctive features in each of the three tissues. Secretory product accumulates within the cisternae of the Golgi apparatus that dilate to form the Golgi vacuoles. The vacuoles apparently separate, and secretory material undergoes further condensation within them. These "secretory vacuoles" possess acid phosphatase activity and may thus be considered lysosomes. The membranes of the Golgi apparatus are without acid phosphatase activity but show high levels of thiaminepyrophosphatase activity. The endoplasmic reticulum also hydrolyzes thiaminepyrophosphate but at a lower rate; it hydrolyzes the diphosphates of uridine, guanosine, and inosine rapidly. These observations and the electron microscopic images are consistent with the view that the cytomembranes are in a dynamic state of flux, movement, and transformation in the living cell, and that smooth surfaced derivatives of the endoplasmic reticulum become refashioned into the Golgi membranes as the Golgi membranes are being refashioned into those that delimit secretory vacuoles. The variations encountered in the two hepatomas are described. The electron microscope literature dealing with the relations of the Golgi apparatus to secretory granules, on the one hand, and the endoplasmic reticulum, on the other, is reviewed briefly.

Phospholipase A2 activation by melittin causes amylase release from exocrine pancreas

1989 ◽  
Vol 67 (5) ◽  
pp. 411-416 ◽  
Author(s):  
Seymour Heisler
Keyword(s):  
Arachidonic Acid ◽  
Exocrine Pancreas ◽  
Phospholipase A ◽  
Pancreatic Acinar Cells ◽  
Secretory Process ◽  
Acid Oxidation ◽  
Amylase Secretion ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Amylase Release

Phospholipase A2-induced deacylation of membrane phospholipids is associated with changes in membrane fluidity. The importance of this reaction in the pancreatic amylase secretory process was tested using melittin, a phospholipase A2 stimulating peptide. Phospholipase A2 activity (using [3H]arachidonic acid release as an index) and amylase secretion were both increased in a time- and concentration-dependent manner by melittin. Phospholipids prelabelled with [3H]oleic acid or [14C]linoleic acid also released radioactive free fatty acids in response to melittin. Prostaglandin synthesis was not involved in the melittin response, since inhibitors of arachidonic acid oxidation (indomethacin, 5,8,11,14-eicosatetraynoic acid) did not alter the ability of melittin to release [3H]arachidonic acid or amylase. When melittin was co-applied with carbachol, cholecystokinin octapeptide, or vasoactive intestinal peptide, amylase secretion was additive. The effect of melittin on both fatty acid and amylase release was dependent on extracellular calcium, though melittin's effects were not dependent on the intracellular accumulation of second messengers such as calcium or cAMP. The data suggest that activation of phospholipase A2 by melittin results in the triggering of the secretory process in exocrine pancreas by a different mechanism than that for other pancreatic secretagogues.Key words: melittin, phospholipase A2, pancreatic acinar cells, amylase secretion.

scholarly journals Immunohistochemical Localization of Monoamine Oxidase Type B in Pancreatic Islets of the Rat

2005 ◽  
Vol 53 (9) ◽  
pp. 1149-1158 ◽  
Author(s):  
Yu-Hong Huang ◽  
Akio Ito ◽  
Ryohachi Arai
Keyword(s):  
B Cells ◽  
Monoamine Oxidase ◽  
Pancreatic Islets ◽  
Pancreatic Islet ◽  
Secretory Granules ◽  
Secretory Process ◽  
Type B ◽  
Electron Microscopic ◽  
Double Labeling ◽  
Outer Membranes

Monoamine oxidase (MAO) is regarded as a mitochondrial enzyme. This enzyme localizes on the outer membrane of mitochondria. There are two kinds of MAO isozymes, MAO type A (MAOA) and type B (MAOB). Previous studies have shown that MAOB activity is found in the pancreatic islets. This activity in the islets is increased by the fasting-induced decrease of plasma glucose level. Islet B cells contain monoamines in their secretory granules. These monoamines inhibit the secretion of insulin from the B cells. MAOB is active in degrading monoamines. Therefore, MAOB may influence the insulin-secretory process by regulating the stores of monoamines in the B cells. However, it has not been determined whether MAOB is localized on B cells or other cell types of the islets. In the present study, we used both double-labeling immunofluorescence histochemical and electron microscopic immunohistochemical methods to examine the subcellular localization of MAOB in rat pancreatic islets. MAOB was found in the mitochondrial outer membranes of glucagon-secreting cells (A cells), insulin-secreting cells (B cells), and some pancreatic polypeptide (PP)-secreting cells (PP cells), but no MAOB was found in somato-statin-secreting cells (D cells), nor in certain other PP cells. There were two kinds of mitochondria in pancreatic islet B cells: one contains MAOB on their outer membranes, but a substantial proportion of them lack this enzyme. Our findings indicate that pancreatic islet B cells contain MAOB on their mitochondrial outer membranes, and this enzyme may be involved in the regulation of monoamine levels and insulin secretion in the B cells.

scholarly journals Immunohistochemical localization of pancreatic exocrine enzymes in normal and neoplastic pancreatic acinar epithelium of rat.

1981 ◽  
Vol 29 (2) ◽  
pp. 309-313 ◽  
Author(s):  
L J Hansen ◽  
M Mangkornkanok/Mark ◽  
J K Reddy
Keyword(s):  
Secretory Granules ◽  
Acinar Cells ◽  
Immunohistochemical Localization ◽  
Model Systems ◽  
Secretory Process ◽  
Secretory Proteins ◽  
Variable Extent ◽  
Immunofluorescent Technique ◽  
Pancreatic Exocrine ◽  
Indirect Immunofluorescent

The transplantable pancreatic acinar carcinomas of rat established recently provide useful model systems to examine the composition of secretory proteins as well as the secretory process in transformed pancreatic exocrine epithelium. The neoplastic acinar cells exhibit considerable variation in the extent of cytodifferentiation. In the present study the enzymatic profile of this heterogeneous tumor cell population has been investigated by the indirect immunofluorescent technique using antibodies against six pancreatic enzymes. By immunofluorescence, all neoplastic cells stained positively for the six enzymes tested: amylase, lipase, carboxypeptidase A, chymotrypsinogen, trypsinogen, and ribonuclease. Some variability in the intensity of immunofluorescence was noted, suggesting possible quantitative differences in the content of a given enzyme among tumor cells. These observations suggest that neoplastic acinar cells with or without secretory granules contain secretory proteins, but to a variable extent.

scholarly journals Cytochemical localization of acid phosphatase and trimetaphosphatase activities in exocrine acinar cells.

1980 ◽  
Vol 28 (1) ◽  
pp. 78-81 ◽  
Author(s):  
C Oliver
Keyword(s):  
Acid Phosphatase ◽  
Lysosomal Enzyme ◽  
Secretory Granules ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Metal Chelation ◽  
Acid Hydrolases ◽  
Cytochemical Localization ◽  
Capture Method ◽  
Secondary Lysosomes

Acid phosphatase activity, a lysosomal marker, is commonly demonstrated using the Gomori technique with cytidine 5'-monophosphate or beta-glycerophosphate as substrate. Using this lead capture method on mouse and rat exorbital lacrimal, parotid, and pancreatic acinar cells, reaction product was localized in GERL, forming secretory granules, and secondary lysosomes. However, a different cytochemical localization was observed for inorganic trimetaphosphatase, another lysosomal enzyme. When the technique for trimetaphosphatase activity, a metal chelation method, was applied to exocrine acinar cells, reaction produce was conspicuously absent from GERL and forming secretory granules, but was present in secondary lysosomes, occasionally in Golgi saccules, and in previously unreported basal elongated lysosomes. The differences in the localization of the two enzymatic activities emphasizes the importance of employing more than one substrate where possible, and raises questions concerning the mechanism of delivery of acid hydrolases to secondary lysosomes.

EM radioautographic studies on the synthesis and transport of phosphatidylcholine in the parotid acinar cells of isoproterenol-treated rats

1978 ◽  
Vol 36 (2) ◽  
pp. 62-63
Author(s):  
Shohei Yamashina
Keyword(s):  
Body Weight ◽  
Intracellular Transport ◽  
Secretory Granules ◽  
Secretory Process ◽  
Parotid Glands ◽  
Electron Microscopic ◽  
Granule Formation ◽  
Intracellular Movement ◽  
Female Wistar Rats ◽  
Secretory Products

The secretory process of the exocrine cells includes: 1) synthesis of secretory materials, 2) intracellular transport and packaging in secretory granules, 3) exocyto- tic discharge responding to secretory stimuli and 4) repair of excess plasma membrane. According to the concept by Palade, synthesis and intracellular transport of secretory products are completed within the surrounding membranes. It is particularly interesting to analyze the dynamic aspects of the membranous container under the brisk stage of secretion granule formation. Since phosphatidylcholine(PC) is well known as one of the ubiquitous constituents of biological membranes, the present study was undertaken to examine the incorporation of [3H]-choline into PC and intracellular movement of labelled PC in the parotid gland of stimulated rats by the administration with isoproterenol (IPR) by means of electron microscopic radioautography,Female Wistar rats(200g body weight) were injected intraperitoneally with isopro- terenol-HCL(8mg/100g body weight). Every 2 hours ranging from 0 to 24 hours both sides of the parotid glands were removed and dissected into pieces of lobules.

scholarly journals ELECTRON MICROSCOPIC LOCALIZATION OF GLYCOPROTEINS IN PITUITARY CELLS OF DUCK AND QUAIL

1971 ◽  
Vol 19 (12) ◽  
pp. 775-797 ◽  
Author(s):  
ANDRÉE TIXIER-VIDAL ◽  
RENÉE PICART
Keyword(s):  
Endoplasmic Reticulum ◽  
Acid Phosphatase ◽  
Phosphatase Activity ◽  
Acid Phosphatase Activity ◽  
Secretory Granules ◽  
Periodic Acid ◽  
Pituitary Cells ◽  
Electron Microscopic ◽  
Gonadotropic Cells ◽  
Dense Bodies

Structures demonstrating the presence of glycoproteins, acid phosphatase activity and OsO4 impregnation were localized by means of the electron microscope in duck and in quail pituitary cells. Two methods for the electron microscopic demonstration of glycoproteins were used: a chromic acid-phosphotungstic acid mixture on glycol-methacrylate-embedded tissues, and the periodic acid-thiocarbohydrazide-silver proteinate technique. Both methods showed glycoproteins in the following sites: ( a) the secretory granules in three types of cells (A, B, C) which are part of the seven different cells of the avian pituitary; ( b) the several kinds of dense bodies which are richer in reaction product than the secretory granules. A correlation with previous studies on similar species of birds is helpful in identifying each of the three positive types of cells as thyrotropic cell (A), prolactin cell (B) and gonadotropic cell (C). The presence of glycoproteins within the Golgi saccules (on condensing granules) was found with the periodic acid-thiocarbohydrazide-silver proteinate method in these gonadotropic cells only. In gonadotropic and thyrotropic cells, acid phosphatase activity is weak in the inner Golgi saccules and strong in the "Golgi Endoplasmic Reticulum Lysosomes" system, in the lysosomes, in the dense bodies and in the vacuolated dense bodies. The structures which are richest in glycoproteins are also those which have the most acid phosphatase activity. On the contrary, OsO4-stained structures in duck gonadotropic cells (nuclear pericisterna, rough endoplasmic reticulum, cisternae and outer Golgi saccules) have no glycoproteins or acid phosphatase activity.

Sign in / Sign up

Export Citation Format

Share Document