Tyrosine kinase regulates epithelial sodium transport in A6 cells.
Am J Physiol
; 264(1 Pt 1): C246-50, 1993 Jan.
Article
in En
| MEDLINE
| ID: mdl-8430772
ABSTRACT
Insulin increases epithelial Na+ reabsorption, and many of its actions involve tyrosine kinase. We used tyrosine kinase inhibitors to examine the role of tyrosine kinase in the action of insulin. Pretreatment of Na+ transporting cells with tyrosine kinase inhibitors attenuates the subsequent action of insulin, suggesting that the action of insulin on epithelial Na+ transport involves tyrosine kinase activity. In addition to their effect on insulin-induced Na+ transport, the tyrosine kinase inhibitors also significantly reduce Na+ transport in Na(+)-transporting epithelial cells, suggesting that there is a significant tonic tyrosine kinase activity that modulates epithelial Na+ transport. Using patch-clamp methods, we found that one inhibitor, genistein, reduces the number of active Na+ channels in cell-attached patches without significantly affecting the open probability of any remaining channels. The effects of the tyrosine kinase inhibitors are not due to inhibition of protein kinase A (PKA), since H89, a PKA inhibitor, does not affect Na+ transport of control cells (as the tyrosine kinase inhibitors do), and the tyrosine kinase inhibitor, genistein or tyrphostin 23, does not alter the stimulation of ion transport by 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate, a membrane-permeable adenosine 3',5'-cyclic monophosphate analogue (as H89 does).
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sodium
/
Protein-Tyrosine Kinases
/
Tyrphostins
/
Nephrons
Limits:
Animals
Language:
En
Journal:
Am J Physiol
Year:
1993
Document type:
Article