The subcellular localization of the incorporation of 2-(3H)-myoinositol into Upids has been studied in isolated pancreatic islets of the rat. The recovery of lipid-bound myoinositol increased with time in the nuclear, mitochondriai, microsomal, and secretory granule fractions. The utilization of a nitration technique for the more complete separation of mitochondriai and secretory granule elements permitted us to show that the recovery of lipld-bound 2-(3H)-myoinositol increased most rapidly in the secretory granule fraction. A 30-minute exposure of prelabeled islets to a stimulatory concentration of D-glucose (3.0 mg./ml.) resulted in a statistically significant decrease in the amount of lipid-bound 2-(3H)-myoinositol that was recovered from the secretory granule fraction (p < 0.001). In contrast, exposure of islets to the elevated glucose concentration had no statistically significant effect on the recovery of Upid-bound radioactivity from other subcellular fractions. Since the majority of lipid-bound radioactivity associated with the secretory granule fraction could be recovered with the presumptive secretory granule membranes, these data suggest that the hydrolysis of phosphatidylinositol that accompanies glucose-induced insulin secretion from the rat pancreatic islet may be localized to the beta granule and, in particular, to it's limiting membrane.
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Original Contributions|
December 01 1977
Subcellular Localization of the Alterations in Phosphatidylinositol Metabolism Following Glucose-induced Insulin Release from Rat Pancreatic Islets
Rex S Clements, Jr, MD;
Rex S Clements, Jr, MD
Department of Medicine, University of Alabama School of Medicine, Birmingham, Alabama, and the Department of Physiology and Biophysics and School of Basic Medical Sciences, University of Illinois
Urbana, Illinois
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William B Rhoten, PhD;
William B Rhoten, PhD
Department of Medicine, University of Alabama School of Medicine, Birmingham, Alabama, and the Department of Physiology and Biophysics and School of Basic Medical Sciences, University of Illinois
Urbana, Illinois
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Willard R Starnes, MS
Willard R Starnes, MS
Department of Medicine, University of Alabama School of Medicine, Birmingham, Alabama, and the Department of Physiology and Biophysics and School of Basic Medical Sciences, University of Illinois
Urbana, Illinois
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Address reprint requests to Rex S. Clements, Jr., M.D., Veterans Administration Hospital, 700 South 19 Street, Birmingham, AL 35233.
Citation
Rex S Clements, William B Rhoten, Willard R Starnes; Subcellular Localization of the Alterations in Phosphatidylinositol Metabolism Following Glucose-induced Insulin Release from Rat Pancreatic Islets. Diabetes 1 December 1977; 26 (12): 1109–1116. https://doi.org/10.2337/diab.26.12.1109
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