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Measurements of cytoplasmic free Ca 2+ concentration in human pancreatic islets and insulinoma cells
Author(s) -
Kindmark Hendrik,
Köhler Martin,
Nilsson Thomas,
Arkhammar Per,
Wiechel Karl-Ludvig,
Rorsman Patrik,
Efendić Suad,
Berggren Per-Olaf
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)81309-v
Subject(s) - tolbutamide , diazoxide , pancreatic islets , medicine , endocrinology , insulinoma , extracellular , depolarization , chemistry , cytoplasm , islet , insulin , biology , biochemistry
In human pancreatic islets an increase in the glucose concentration from 3 to 20 mM raised the free cytoplasmic Ca 2+ concentration ([Ca 2+ ] i ), an effect being reversible upon withdrawal of the sugar. Depolarization with a high concentration of K + or the sulphonylurea tolbutamide also raised [Ca 2+ ] i . Addition of extracellular ATP produced a transient rapid rise in [Ca 2+ ] i . Oscillations in [Ca 2+ ] i were observed in the presence of 10 mM glucose. Insulinoma cells responded to glucose and tolbutamide with increases in [Ca 2+ ] i , whereas the sulphonamide diazoxide caused a decrease in [Ca 2+ ] i . These findings confirm previous results obtained in rodent β‐cells.