We have previously shown that in the intact rat: (1) the inhibition of glucose-induced insulin release caused by vincristine occurred in the presence or absence of morphologic disruption of the beta-cell microtubules; and (2) vincristine, however, failed to inhibit arginine-induced insulin release, even in the presence of a marked disruption of the beta-cell microtubules. The present study further evaluated the mechanism of inhibition of vincristine on glucose-induced insulin release in the intact rat. In the first series of studies, glucose (500 mg/kg) was infused over 1 min into fasting rats with indwelling vascular catheters. Five minutes later, vincristine (0.15 mg/kg i.v.) or vehicle (control) was injected. Sixty minutes after vincristine or vehicle treatment, insulin release in response to a 150-mg i.v. glucose pulse was examined. Serum insulin and glucose levels were similar at all time intervals in the vincristine-treated and the control rats. In the next series of studies, the experiments were repeated as above, except arginine (100 mg/kg), instead of glucose, was infused over 1 min before vincristine or vehicle treatment. In these studies, serum insulin in response to a glucose pulse was significantly inhibited in the vincristine-treated rats as compared with control rats. Therefore, in the intact rat, prior exposure to glucose but not arginine protected the beta-cell from the inhibitory effect of vincristine on glucose-induced insulin release. These findings, along with our previous observations, support the concept that arginine-induced insulin release is mediated via mechanisms other than those involved in glucose-induced insulin release and suggest that the in vivo effect of vincristine on glucose-induced insulin release is mediated via alteration of the beta-cell glucose receptors rather than microtubular structures.
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September 01 1982
Glucose but not Arginine Prevents the Inhibitory Effect of Vincristine on Glucose-induced Insulin Release
Jayendra H Shah;
Jayendra H Shah
Section of Endocrinology and Metabolism, Departments of Medicine and Nuclear Medicine, Veterans Administration West Side Medical Center, and Abraham Lincoln School of Medicine, University of Illinois College of Medicine
Chicago, Illinois 60612
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Renee Schickler;
Renee Schickler
Section of Endocrinology and Metabolism, Departments of Medicine and Nuclear Medicine, Veterans Administration West Side Medical Center, and Abraham Lincoln School of Medicine, University of Illinois College of Medicine
Chicago, Illinois 60612
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Charles Hurks;
Charles Hurks
Section of Endocrinology and Metabolism, Departments of Medicine and Nuclear Medicine, Veterans Administration West Side Medical Center, and Abraham Lincoln School of Medicine, University of Illinois College of Medicine
Chicago, Illinois 60612
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Bernard Stevens
Bernard Stevens
Section of Endocrinology and Metabolism, Departments of Medicine and Nuclear Medicine, Veterans Administration West Side Medical Center, and Abraham Lincoln School of Medicine, University of Illinois College of Medicine
Chicago, Illinois 60612
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Address reprint requests to Jayendra H. Shah, M.D., VA West Side Medical Center (M.P. 115), P.O. Box 8195, Chicago, Illinois 60680.
Citation
Jayendra H Shah, Renee Schickler, Charles Hurks, Bernard Stevens; Glucose but not Arginine Prevents the Inhibitory Effect of Vincristine on Glucose-induced Insulin Release. Diabetes 1 September 1982; 31 (9): 834–837. https://doi.org/10.2337/diab.31.9.834
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