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DOI: 10.1055/s-0028-1093913
© Georg Thieme Verlag KG Stuttgart · New York
Acute Effects of Alloxan on the Metabolism and Insulin Secretion of the Pancreatic B-Cell
Publication History
Publication Date:
07 January 2009 (online)
Abstract
Acute effects of alloxan on the metabolism and insulin secretion of the pancreatic B-cell were studied in islets isolated from obese-hyperglycemic mice killed 10 minutes after an intravenous injection of 100 mg/kg of the drug. The islets displayed a normal endogenous respiration but alloxan prevented a raise in islet oxygen uptake which could be observed in the control islets after addition of glucose, citrate or oxaloacetate. A pronounced respiratory stimulation observed in the presence of succinate was, however, not affected by alloxan. Neither was there any change of the anaerobic glycolytic rate of the islet cells after alloxan injection whereas the oxidation of [U-14C] D-glucose and [U-14C] D-mannose was stronlgy inhibited. No change was observed in the rate of [U-14C] pyruvate oxidation. While alloxan caused a raised insulin release in the presence of low glucose it inhibited insulin release in response to high glucose and theophylline. It is concluded that alloxan has an acute inhibitory effect on islet glucose degradation and also inhibits the glucose stimulated insulin release. It cannot so far be decided whether the observed metabolic and secretory disturbance of the islet cells is a manifestation of a primary molecular effect of alloxan or a secondary phenomenon.
Key words
Experimental Diabetes Mellitus - Alloxan - Obese-Hyperglycemic Mice - Isolated Pancreatic Islets - Oxygen Uptake - Anaerobic Glycolysis - Glucose Oxidation - Mannose Oxidation - Insulin Release