| Autor: |
Pershadsingh, Harrihar A., Lee, L.-Y., Snowdowne, Kenneth W. |
| Zdroj: |
FEBS Letters; January 1989, Vol. 244 Issue: 1 p89-92, 4p |
| Abstrakt: |
The objective of these studies is to identify and characterize Ca 2+-transport systems that may be of potential importance in the action of Ca 2+-mobilizing hormones in the adipocyte. Using the Ca 2+-sensitive photoprotein, aequorin, [Ca 2+] iwas estimated to be 0.15 μM, assuming an intracellular [Mg 2+] of 1 mM. Substitution of Na +with choline +caused a transient increase in [Ca 2+] iwhich was inversely related to extracellular [Na +], consistent with operation of a mediated Na +-Ca 2+exchange system. The stoichiometry was 3Na +:Ca 2+. Elevation of extracellular K +caused an increase in [Ca 2+] ithat was blocked by the Ca 2+channel antagonist, diltiazem, by omitting extracellular Ca 2+, or by substituting Sr 2+for Ca 2+. These findings indicate the presence of an Na +-Ca 2+exchanger and voltage-sensitive Ca 2+channels in adipocytes. |
| Databáze: |
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