Role of Ca2+ in the stimulation of glucose transport by insulin in adipocytes
The Korean Journal of Physiology and Pharmacology
;
: 357-364, 1999.
Article
in English
| WPRIM
| ID: wpr-728238
ABSTRACT
We investigated the role of Ca2+ and protein kinases/phosphatases in the stimulatory effect of insulin on glucose transport. In isolated rat adipocytes, the simple omission of CaCl2 from the incubation medium significantly reduced, but did not abolish, insulin-stimulated 2-deoxy glucose (2-DG) uptake. Pre-loading adipocytes with intracellular Ca2+ chelator, 5,5'-dimethyl bis (o-aminophenoxy)ethane-N,N,N'N' tetraacetic acetoxymethyl ester (5,5'-dimethyl BAPTA/AM) completely blocked the stimulation. Insulin raised intracellular Ca2+ concentration ((Ca2+)i) about 1.7 times the basal level of 72+/-5 nM, and 5,5'-dimethyl BAPTA/AM kept it constant at the basal level. This correlation between insulin-induced increases in 2-DG uptake and (Ca2+)i indicates that the elevation of (Ca2+)i may be prerequisite for the stimulation of glucose transport. Studies with inhibitors (ML-9, KN-62, cyclosporin A) of Ca2+-calmodulin dependent protein kinases/phosphatases also indicate an involvement of intracellular Ca2+. Additional studies with okadaic acid and calyculin A, protein phosphatase-1 (PP-1) and 2A (PP-2A) inhibitors, indicate an involvement of PP-1 in insulin action on 2-DG uptake. These results indicate an involvement of Ca2+-dependent signaling pathway in insulin action on glucose transport.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Staphylococcal Protein A
/
Cyclosporine
/
Adipocytes
/
Okadaic Acid
/
Glucose
/
Insulin
Limits:
Animals
Language:
English
Journal:
The Korean Journal of Physiology and Pharmacology
Year:
1999
Type:
Article
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