Dispersed islet cells from noninbred ob/ob mice were cultured for 3 days with 3 or 20 mM D-glucose and silver stained according to Rambourg et al. Two tinctorial subsets of dark and light intracellular granules were analyzed by morphometry at the ultrastructural level. The two types of granules were similar in size and shape. However, with 3 mM glucose the dark granule cores were surrounded by larger vesicles than the light granules. With 20 mM glucose, both types of granule vesicles and cores became smaller and dark-granule cores became more rounded, compared with cultures with 3 mM glucose. The higher glucose concentration also induced a marked decrease in the number (−84%) and volume density (−90%) of dark granules. In contrast, the number of light granules increased (+60%) with maintenance of their volume density. We suggest that the dark Rambourg-positive and the light Rambourg-negative β-cell granules are functionally distinct subsets. The dark granules are probably engaged in insulin discharge. We discuss the unclear role of the light granules with a view to previously postulated heterogeneities of the insulin granule pool and their significance for exocytosis and intracellular hormone degradation.
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February 01 1988
Morphometry of Rambourg-Positive and Rambourg-Negative β-Cell Granules After Culture With Low and High Glucose Concentrations
Robert Norlund;
Robert Norlund
Department of Histology and Cell Biology, University of Umeå
Sweden
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Lena Norlund;
Lena Norlund
Department of Histology and Cell Biology, University of Umeå
Sweden
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Inge-Bert Täljedal
Inge-Bert Täljedal
Department of Histology and Cell Biology, University of Umeå
Sweden
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Address reprint requests to Dr. Robert Norlund, Department of Histology and Cell Biology, University of Umeå, S-901 87 Umeå, Sweden.
Diabetes 1988;37(2):194–199
Article history
Received:
April 15 1987
Revision Received:
July 28 1987
Accepted:
July 28 1987
PubMed:
2455667
Citation
Robert Norlund, Lena Norlund, Inge-Bert Täljedal; Morphometry of Rambourg-Positive and Rambourg-Negative β-Cell Granules After Culture With Low and High Glucose Concentrations. Diabetes 1 February 1988; 37 (2): 194–199. https://doi.org/10.2337/diab.37.2.194
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