Cyclic AMP Phosphodiesterases of Human and Rat Islets of Langerhans: Contributions of Types III and IV to the Modulation of Insulin Secretion

1995 ◽  
Vol 217 (3) ◽  
pp. 916-923 ◽  
Author(s):  
J.C. Parker ◽  
M.A. Vanvolkenburg ◽  
R.J. Ketchum ◽  
K.L. Brayman ◽  
K.M. Andrews
Keyword(s):  
Insulin Secretion ◽  
Cyclic Amp ◽  
Islets Of Langerhans ◽  
Rat Islets ◽  
Rat Islets Of Langerhans

scholarly journals Stimulation of Adenylate Cyclase by Ca2+ and Calmodulin in Rat Islets of Langerhans: Explanation for the Glucose-induced Increase in Cyclic AMP Levels

Diabetes ◽  
1980 ◽  
Vol 29 (1) ◽  
pp. 74-77 ◽  
Author(s):  
G. W. G. Sharp ◽  
D. E. Wiedenkeller ◽  
D. Kaelin ◽  
E. G. Siegel ◽  
C. B. Wollheim
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Islets Of Langerhans ◽  
Rat Islets ◽  
Rat Islets Of Langerhans ◽  
Stimulation Of

Immunoprecipitation of a pertussis toxin substrate of the Go family from rat islets of Langerhans

1992 ◽  
Vol 12 (2) ◽  
pp. 95-100 ◽  
Author(s):  
Nicholas S. Berrow ◽  
Roger D. Hurst ◽  
Susan L. F. Chan ◽  
Noel G. Morgan
Keyword(s):  
Molecular Weight ◽  
Insulin Secretion ◽  
Adenylate Cyclase ◽  
G Protein ◽  
G Proteins ◽  
Islets Of Langerhans ◽  
Pertussis Toxin ◽  
Inhibitory Receptors ◽  
Rat Islets ◽  
Rat Islets Of Langerhans

Rat islets express a pertussis toxin sensitive G-protein involved in receptor-mediated inhibition of insulin secretion. This has been assumed previously to represent “Gi” which couples inhibitory receptors to adenylate cyclase. Incubation of islet G-proteins with32P-NAD and pertussis toxin resulted in the labelling of a band of molecular weight 40,000. This band was very broad and did not allow resolution of individual components. Incubation of the radiolabelled proteins with an anti-Go antiserum resulted in specific immunoprecipitation of a32P-labelled band. These results demonstrate that the complement of pertussis toxin sensitive G-proteins in rat islets includes Go.

Relationships between energy level and insulin secretion in isolated rat islets of langerhans

1992 ◽  
Vol 43 (8) ◽  
pp. 1859-1864 ◽  
Author(s):  
Mitsuaki Ohta ◽  
David Nelson ◽  
Jeanne M. Wilson ◽  
Martin D. Meglasson ◽  
Maria Erecińska
Keyword(s):  
Insulin Secretion ◽  
Energy Level ◽  
Islets Of Langerhans ◽  
Rat Islets ◽  
Isolated Rat Islets ◽  
Rat Islets Of Langerhans ◽  
Isolated Rat

scholarly journals Studies on the role of inositol trisphosphate in the regulation of insulin secretion from isolated rat islets of Langerhans

1985 ◽  
Vol 228 (3) ◽  
pp. 713-718 ◽  
Author(s):  
N G Morgan ◽  
G M Rumford ◽  
W Montague
Keyword(s):  
Insulin Secretion ◽  
Islets Of Langerhans ◽  
Islet Cells ◽  
Inositol Trisphosphate ◽  
Rat Islets ◽  
Isolated Rat Islets ◽  
Rat Islets Of Langerhans ◽  
Isolated Rat ◽  
Stimulation Of

Glucose (20 mM) and carbachol (1 mM) produced a rapid increase in [3H]inositol trisphosphate (InsP3) formation in isolated rat islets of Langerhans prelabelled with myo-[3H]inositol. The magnitude of the increase in InsP3 formation was similar when either agent was used alone and was additive when they were used together. In islets prelabelled with 45Ca2+ and treated with carbachol (1 mM), the rise in InsP3 correlated with a rapid, transient, release of 45Ca2+ from the cells, consistent with mobilization of 45Ca2+ from an intracellular pool. Under these conditions, however, insulin secretion was not increased. In contrast, islets prelabelled with 45Ca2+ and exposed to 20mM-glucose exhibited a delayed and decreased 45Ca2+ efflux, but released 7-8-fold more insulin than did those exposed to carbachol. Depletion of extracellular Ca2+ failed to modify the increase in InsP3 elicited by either glucose or carbachol, whereas it selectively inhibited the efflux of 45Ca2+ induced by glucose in preloaded islets. Under these conditions, however, glucose was still able to induce a small stimulation of the first phase of insulin secretion. These results demonstrate that polyphosphoinositide metabolism, Ca2+ mobilization and insulin release can all be dissociated in islet cells, and suggest that glucose and carbachol regulate these parameters by different mechanisms.

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