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

Abstract

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, ET A receptor antagonist, 20 minutes before ET-1 (ET A antagonist group) and administration of BQ-788, ET B receptor antagonist, 20 minutes before ET-1(ET B 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-1 A receptor play a crucial role in age-related change in renal function.