ISSN:
1432-0428
Keywords:
Alloxan
;
cyclic AMP
;
isolated islets
;
insulin secretion
;
glucose metabolism
;
3-0-methylglucose
;
glyceraldehyde
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Insulin secretion was stimulated and cyclic adenosine 3′, 5′-monophosphate (cAMP) levels were elevated in isolated rat islets by 27.5 mmol/l glucose. Alloxan caused a dose-dependent decrease in both variables with complete obliteration of insulin release at a concentration of 1.25 mmol/l. D-glucose, in the presence or absence of extracellular calcium, or 3-0-methyl-D-glucose (both at 27.5 mmol/l) protected completely against the effects of alloxan on both glucose-induced insulin release and cAMP levels. 3-0-Methylglucose did not stimulate insulin secretion or elevate cAMP and did not interfere with glucose-stimulated secretion or elevation of cAMP. When glucose-stimulated insulin release was abolished by alloxan, the metabolism of glucose, determined by the rate of3H2O formation from [5-3H] glucose, was depressed by 20%. It is concluded that alloxan altered the adenylate cyclase system such that it could no longer be stimulated by glucose. Glucose-stimulated insulin secretion or elevation of cAMP did not appear essential for glucose to protect against alloxan. Protection by 3-0-methylglucose did not appear to be mediated through an alteration of cAMP metabolism. Alloxan did not inhibit glucose-induced insulin secretion by grossly altering glycolysis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01225460
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