Aging in rats significantly decreased G αs binding and increased G αi(1-3) binding, while reducing tyrosine kinase activity and MAP-K phosphorylation in the kidney cortex.
Aging in rats is associated with altered G-protein binding ratios and reduced MAP-K and tyrosine kinase activity in the kidney cortex, which may contribute to age-related renal decline.
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 G αi(1-3) and G αs , 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 G αs was significantly decreased in the kidney cortex of aging rats compared to young rats, while the GTP/(GTP+GDP) binding ratio of G αi(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 G αi(1-3) and G αs may contribute to the age-related decline in renal tubular and vascular function seen in aging animals.
Parekh et al. (Mon,) conducted a other in Age-related decline in renal function. Aging (14-month-old rats) vs. Young (4-month-old rats) was evaluated on Expression and activity of G-proteins, MAP-K, and tyrosine kinases in renal cortical homogenates. Aging in rats significantly decreased G αs binding and increased G αi(1-3) binding, while reducing tyrosine kinase activity and MAP-K phosphorylation in the kidney cortex.