ISSN:
1432-0428
Keywords:
Islets
;
culture
;
calcium
;
glucose
;
stimulus-secretion coupling
;
beta cells
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The pattern of the increase in cytoplasmic Cai 2+ that glucose produces in beta cells has been reported to be highly variable. Here, we evaluated the influence of the culture duration (1–4 days) and conditions (5–10 mmol/l glucose) on Cai 2+ in normal mouse islets stimulated by glucose. After 1 day of culture in 10 mmol/l glucose, a rise of the glucose concentration from 3 to 15 mmol/l induced a triphasic change of Cai 2+ in the islets. A small initial decrease was followed by a large peak increase and then by regular fast oscillations (∼2.5/min). When the culture was prolonged to 2, 3 and 4 days, the initial decrease became inconsistent and the peak occurred earlier, whereas the oscillations decreased in frequency, increased in duration and eventually disappeared; on day 4 the Cai 2+ rise was sustained. After culture in 5 mmol/l glucose, the pattern of Cai 2+ changes induced by 15 mmol/l glucose was different. The initial decrease was very pronounced, the first peak was delayed and clearly separated from the subsequent oscillations. These were of a mixed type (fast Ca2+ transients on top of slow ones) after 1 day, and of a slow type only after 4 days. These alterations in the Cai 2+ oscillations triggered by glucose could not be ascribed to desynchronization of the signal between different regions of the islets. In conclusion, culturing normal mouse islets in 5 or 10 mmol/l glucose for 1–4 days, markedly alters the characteristics of the changes in Cai 2+ produced by glucose. This pitfall must be borne in mind when studying stimulus-secretion coupling in beta cells from normal or diabetic animals, or from human islets.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00400464
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