Abstract
Background
Renal function declines with age and this may be related to changes in the expression or activity of various signal transduction proteins in the kidney.
Methods
The present study compared the expression and activity of Gαi(1-3) and Gαs, phosphorylation of mitogen activated protein kinases (MAP-K) (44 and 42 kd) and the activity of tyrosine kinase in renal cortical homogenates of young (4-month-old) and aging (14-month-old) rats.
Results
The GTP/(GTP+GDP) binding ratio of Gαs was significantly decreased in the kidney cortex of aging rats compared to young rats, while the GTP/(GTP+GDP) binding ratio of Gαi(1-3) increased significantly in kidney cortex of aging rats. Tyrosine kinase activity and phosphorylation of MAP-K (44 and 42 kd) were also reduced in the kidney cortex of aging rats compared to young rats.
Conclusions
These results suggest that diminished phosphorylation of MAP-K and tyrosine kinase activity as well as changes in the binding of GTP/(GTP+GDP) to Gαi(1-3) and Gαs may contribute to the age-related decline in renal tubular and vascular function seen in aging animals.
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