Effects of Insulinotropic Agents on Cationic Fluxes in Islet Cells

Author(s):  
W. J. Malaisse ◽  
A. Sener ◽  
A. Herchuelz
Keyword(s):  
Author(s):  
Kazuaki Misugi ◽  
Nobuko Misugi ◽  
Hiroshi Yamada

The authors had described the fine structure of a type of pancreatic islet cell, which appeared different from typical alpha and beta cells, and tentatively considered that this third type of granular cell probably represents the D cell (Figure 1).Since silver staining has been widely used to differentiate different types of pancreatic islet cells by light microscopy, an attempt to examine this staining reaction at the electron microscopic level was made.Material and Method: Surgically removed specimens from three infants who suffered from severe hypoglycemia were used. The specimens were fixed and preserved in 20% neutral formalin. Frozen sections, 30 to 40 micron thick, were prepared and they were stained by Bielschowsky's method as modified by Suzuki (2). The stained sections were examined under a microscope and islet tissues were isolated. They were fixed in 1% osmium tetroxide in phosphate buffer for one hour and embedded in Epon 812 following dehydration through a series of alcohols and propylene oxide.


Diabetes mellitus can be defined as chronic metabolic disease which results from either relative or complete absence of insulin by the pancreatic beta islet cells. This in-turn may lead to hyperglycemia due to disturbances in the metabolism of glucose. In the human body, iron is con- sidered to be an effective pro-oxidant and participates in the generation of reactive oxygen species (ROS) such as hydroxyl radical. Because of the poor antioxidant defense mechanism of beta cells (low production of antioxidant enzymes such as catalase, glutathione peroxidase and dismutase), so they are highly prone to iron-induced oxidative stress and iron deposition in it and this will lead to apoptosis, and subsequently insulin deficiency. This iron deposition in beta cells will also lead to insulin resistance by reducing insulin extracting ability of the liver and inhibiting glucose uptake in muscle tissues and fats, this in turn will result in high production of hepatic glucose. Ferritin which is an acute phase reactant protein, that responds to acute stress like trauma, infections, tissue necrosis and surgery, it can produce diabetes mellitus either through inflammation or by increasing iron stores.


1971 ◽  
Vol 67 (2) ◽  
pp. 405-416 ◽  
Author(s):  
E. Nieschlag ◽  
H. Wombacher ◽  
F. J. Kroeger ◽  
L.V. Habighorst

A patient with a metastazing functional islet cell tumour suffering from severe hypoglycaemia was treated with streptozotocin. Four intravenous injections of 1.5 g streptozotocin each were administered in 4 to 6 days intervals. After the 4th injection there were no further episodes of hypoglycaemia, parenteral glucose administration could be stopped and blood sugar and plasma insulin, showing concentrations of up to 405 μU/ml before treatment, reached normal levels. The tumours in the pancreas disappeared and the liver metastases decreased in size and number as judged by arteriography. A hypothesis for the mechanism of action of streptozotocin is proposed. The glucose moiety is considered to facilitate a high affinity to the islet cells whereas the N-methyl-nitrosourea residue serves the active antitumour part of the molecule.


Diabetes ◽  
1980 ◽  
Vol 29 (6) ◽  
pp. 497-500 ◽  
Author(s):  
P. Meda ◽  
E. L. Hooghe-Peters ◽  
L. Orci

Diabetes ◽  
1984 ◽  
Vol 33 (6) ◽  
pp. 556-561 ◽  
Author(s):  
G. Gold ◽  
M. L. Gishizky ◽  
W. L. Chick ◽  
G. M. Grodsky

Diabetes ◽  
1988 ◽  
Vol 37 (8) ◽  
pp. 1123-1128
Author(s):  
N. Welsh ◽  
A. Hallberg ◽  
S. Sandler ◽  
C. Hellerstrom

Diabetes ◽  
1982 ◽  
Vol 31 (3) ◽  
pp. 189-193 ◽  
Author(s):  
Y. Spiess ◽  
M. A. Smith ◽  
W. Vale

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