The Secretory Process in B Cells of the Pancreas

2015 ◽  
pp. 359-388
Author(s):  
Gerald Gold ◽  
Gerold M. Grodsky
Keyword(s):  
B Cells ◽  
Secretory Process

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 Two sites of glucose control of insulin release with distinct dependence on the energy state in pancreatic B-cells

1994 ◽  
Vol 297 (3) ◽  
pp. 455-461 ◽  
Author(s):  
P Detimary ◽  
P Gilon ◽  
M Nenquin ◽  
J C Henquin
Keyword(s):  
Membrane Potential ◽  
B Cells ◽  
Insulin Release ◽  
Cell Function ◽  
Energy State ◽  
Secretory Process ◽  
High K ◽  
Pancreatic B Cells ◽  
Stimulus Secretion Coupling ◽  
Intracellular Targets

The energy state of pancreatic B-cells may influence insulin release at several steps of stimulus-secretion coupling. By closing ATP-sensitive K+ channels (K(+)-ATP channels), a rise in the ATP/ADP ratio may regulate the membrane potential, and hence Ca2+ influx. It may also modulate the effectiveness of Ca2+ on its intracellular targets. To assess the existence of these two roles and determine their relative importance for insulin release, we tested the effects of azide, a mitochondrial poison, on mouse B-cell function under various conditions. During stimulation by glucose alone, when K(+)-ATP channels are controlled by cellular metabolism, azide caused parallel, concentration-dependent (0.5-5 mM), membrane repolarization, decrease in cytosolic Ca2+ concentration [Ca2+]i and inhibition of insulin release. When K(+)-ATP channels were closed pharmacologically (by tolbutamide in high glucose), azide did not repolarize the membrane or decrease [Ca2+]i, and was much less effective in inhibiting insulin release. A similar resistance to azide was observed when K(+)-ATP channels were opened by diazoxide, and high K+ was used to depolarize the membrane and raise [Ca2+]i. In contrast, azide similarly decreased ATP levels and increased ADP levels, thereby lowering the ATP/ADP ratio under all conditions. In conclusion, lowering the ATP/ADP ratio in B-cells can inhibit insulin release even when [Ca2+]i remains high. However, this distal step is much more resistant to a decrease in the energy state of B-cells than is the control of membrane potential by K(+)-ATP channels. Generation of the signal triggering insulin release, high [Ca2+]i, through metabolic control of membrane potential requires a higher global ATP/ADP ratio than does activation of the secretory process itself.

Plasmalemma localisation of inorganic phosphate in B cells pancreas

1978 ◽  
Vol 36 (2) ◽  
pp. 528-529
Author(s):  
F. B. P. Wooding ◽  
K. Pedley ◽  
N. Freinkel ◽  
R. M. C. Dawson
Keyword(s):  
Electron Microscope ◽  
B Cells ◽  
B Cell ◽  
Pancreatic Islets ◽  
High Glucose ◽  
Lead Acetate ◽  
Inorganic Phosphate ◽  
Slight Modification ◽  
Uranyl Acetate ◽  
Lead Phosphate

Freinkel et al (1974) demonstrated that isolated perifused rat pancreatic islets reproduceably release up to 50% of their total inorganic phosphate when the concentration of glucose in the perifusion medium is raised.Using a slight modification of the Libanati and Tandler (1969) method for localising inorganic phosphate by fixation-precipitation with glutaraldehyde-lead acetate we can demonstrate there is a significant deposition of lead phosphate (identified by energy dispersive electron microscope microanalysis) at or on the plasmalemma of the B cell of the islets (Fig 1, 3). Islets after incubation in high glucose show very little precipitate at this or any other site (Fig 2). At higher magnification the precipitate seems to be intracellular (Fig 4) but since any use of osmium or uranyl acetate to increase membrane contrast removes the precipitate of lead phosphate it has not been possible to verify this as yet.

A T.E.M. study of mouse mammary epithelial cell secretory differentiation cultured on collagen and Matrigel

1991 ◽  
Vol 49 ◽  
pp. 188-189
Author(s):  
W.N. Bentham ◽  
V. Rocha
Keyword(s):  
Cell Culture ◽  
Mammary Epithelial ◽  
Secretory Process ◽  
Cell Culture System ◽  
Protein Maturation ◽  
Cell Culture Techniques ◽  
Culture Techniques ◽  
Mouse Mammary Epithelial Cell ◽  
Secretory Differentiation

It has been an interest of our lab to develop a mammary epethelial cell culture system that faithfully duplicates the in vivo condition of the lactating gland. Since the introduction of collagen as a matrix on which cells are cultivated other E.C.M. type matrices have been made available and are used in many cell culture techniques. We have previously demonstrated that cells cultured on collagen and Matrigel do not differentiate as they do in vivo. It seems that these cultures often produce cells that show a disruption in the secretory process. The appearance of large ribosomal studded vesicles, that specifically label with antibody to casein, suggest an interruption of both protein maturation and secretion at the E.R. to golgi transition. In this report we have examined cultures on collagen and Matrigel at relative high and low seeding densities and compared them to cells from the in vivo condition.

Control of Secretory Production in the Isopod Hepatopancreas

1972 ◽  
Vol 30 ◽  
pp. 166-167
Author(s):  
John W. Roberts ◽  
E. R. Witkus
Keyword(s):  
B Cells ◽  
Morphological Data ◽  
Secretory Product ◽  
Secretory Function ◽  
Secretory Material ◽  
Blind Ending ◽  
Secretory Production ◽  
Regenerative Cells ◽  
Immature Cells ◽  
And Storage

The isopod hepatopancreas, as exemplified by Oniscus ascellus. is comprised of four blind-ending diverticula. The regenerative cells at the tip of each diverticula differentiate into either club-shaped B-cells, which serve a secretory function, or into conoid S-cells, which serve in the absorption and storage of nutrients.The glandular B-cells begin producing secretory material with the development of rough endoplasmic reticulum during their process of maturation from the undifferentiated regenerative cells. Cytochemical and morphological data indicate that the hepatopancreas sequentially produces two types of secretory material within the large club-shaped cells. The production of the carbohydrate-like secretory product in immature cells seems to be phased out as the production of the osmiophilic secretion was phased in as the cell matured.

Lymphoproliferative disorders (LPD) involving lungs: T and B cell subsets within pulmonary infiltrates and in peripheral blood

1984 ◽  
Vol 42 ◽  
pp. 700-701
Author(s):  
Irene Stachura ◽  
Milton H. Dalbow ◽  
Michael J. Niemiec ◽  
Matias Pardo ◽  
Gurmukh Singh ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Lymphoproliferative Disorders ◽  
Mixed Population ◽  
Lymphoid Cells ◽  
Lymphomatoid Granulomatosis ◽  
Cell Type ◽  
Cell Surface Antigens ◽  
Pulmonary Infiltrates ◽  
B Cell Subsets

Lymphoid cells were analyzed within pulmonary infiltrates of six patients with lymphoproliferative disorders involving lungs by immunofluorescence and immunoperoxidase techniques utilizing monoclonal antibodies to cell surface antigens T11 (total T), T4 (inducer/helper T), T8 (cytotoxic/suppressor T) and B1 (B cells) and the antisera against heavy (G,A,M) and light (kappa, lambda) immunoglobulin chains. Three patients had pseudolymphoma, two patients had lymphoma and one patient had lymphomatoid granulomatosis.A mixed population of cells was present in tissue infiltrates from the three patients with pseudolymphoma, IgM-kappa producing cells constituted the main B cell type in one patient. In two patients with lymphoma pattern the infiltrates were composed exclusively of T4+ cells and IgG-lambda B cells predominated slightly in the patient with lymphomatoid granulomatosis.

Ca++-ATPase activity in the hepatopancreas cells of Oniscus asellus

1992 ◽  
Vol 50 (1) ◽  
pp. 820-821
Author(s):  
G.M. Vernon ◽  
A. Surace ◽  
R. Witkus
Keyword(s):  
B Cells ◽  
Epithelial Cell ◽  
Atpase Activity ◽  
Calcium Transport ◽  
Carcinus Maenas ◽  
Cell Types ◽  
Molt Cycle ◽  
Copper And Zinc

The hepatopancreas consists of a pair of bilobed tubules comprised of two epithelial cell types. S cells are absorptive and accumulate metals such as copper and zinc. Ca++ concentrations vary between the S and B cells and during the molt cycle. Roer and Dillaman implicated Ca++-ATPase in calcium transport during molting in Carcinus maenas. This study was undertaken to compare the localization of Ca++-ATPase activity in the S and B cells during intermolt.

A pre-embedding double staining procedure used to observe the effect of fixation on the activity of intercellular adhesion molecule on T and B cells

1990 ◽  
Vol 48 (3) ◽  
pp. 378-379
Author(s):  
Jane E. Ramberg ◽  
Shigeto Tohma ◽  
Peter E. Lipsky
Keyword(s):  
B Cells ◽  
Adhesion Molecule ◽  
Colloidal Gold ◽  
Intercellular Adhesion ◽  
Intercellular Adhesion Molecule ◽  
Staining Procedure ◽  
Double Staining ◽  
T And B Cells ◽  
Microtiter Plates ◽  
Streptavidin Peroxidase

Intercellular adhesion molecule (ICAM-1) appears to be a ligand for LFA-1 dependent adhesion in T cell mediated cytotoxcity. It is found on cells of both hematopoietic and non-hematopoietic origin. While observing the activity of ICAM-1 on the surfaces of interacting T and B cells, we found that we could successfully carry out a pre-embedding double staining procedure utilizing both colloidal gold and peroxidase conjugated reagents.On 24-well microtiter plates, mitomycin-treated T4 cells were stimulated with 64.1 (anti-CD3) for one hour before the addition, in some instances, of B cells. Following a 12-48 hour incubation at 38°C, the cells were washed and then immunostained with a colloidal gold conjugated RFB-4 (anti-CD22); biotinylated R6.5 (anti-ICAM-1); followed by streptavidin/peroxidase. This method allowed us to observe two different antigens without concern about possible cross-reaction of reagents. Because we suspected ICAM-1 and R6.5 were sensitive to fixation, we tried varying concentrations of fresh paraformaldehyde before R6.5, after R6.5 and after streptavidin/peroxidase. All immunostaining and washing was done on ice with ice cold reagents.

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