Influence of Endothelin-1 on Age-related Changes in Renal Function in Male Rats

The kidney is one of the organs that are highly susceptible to age-related tissue
damage. Several human and animal studies show decline in renal function with age.
We examined the effect of endothelin-1 on age-related changes on renal function and
whether this effect is mediated by ET-1 receptor types A or B. Also, we investigated
the hemodynamic response to ET-1 and ET-1 receptor antagonist. Two age groups of
male rats were used: young (4–5 months) and old (19–20 months). Each group was
subdivided into four subgroups in which hemodynamic and renal function data were
measured after administration of saline (control group), acute intravenous injection
of endothelin-1 (ET-1 group), administration of BQ-123, ETA receptor antagonist, 20
minutes before ET-1 (ETA antagonist group) and administration of BQ-788, ETB
receptor antagonist, 20 minutes before ET-1(ETB antagonist group). We found that
aging is associated with elevated mean arterial blood pressure and reduced renal
function data. ET-1 injection resulted in more pressor response in old rats and more
reduction of renal function data in young rats. Pretreatment with BQ-123 improved
renal function with more augmentation in old rats while BQ-788 pretreatment has no
effect on renal function. These results indicated that ET-1 and ET-1A receptor play a
crucial role in age-related change in renal function.