Morphometry of Rambourg-positive and Rambourg-negative beta-cell granules after culture with low and high glucose concentrations
Morphometry of Rambourg-positive and Rambourg-negative beta-cell granules after culture with low and high glucose concentrations. R Norlund , L Norlund and I B Täljedal Department of Histology and Cell Biology, University of Umeå, Sweden. Abstract Dispersed islet cells from noninbred ob/ob mice were...
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Published in | Diabetes (New York, N.Y.) Vol. 37; no. 2; pp. 194 - 199 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
American Diabetes Association
01.02.1988
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Online Access | Get full text |
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Summary: | Morphometry of Rambourg-positive and Rambourg-negative beta-cell granules after culture with low and high glucose concentrations.
R Norlund ,
L Norlund and
I B Täljedal
Department of Histology and Cell Biology, University of Umeå, Sweden.
Abstract
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
beta-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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ISSN: | 0012-1797 1939-327X 0012-1797 |
DOI: | 10.2337/diabetes.37.2.194 |