Angiotensin II-dependent induction of AT2 receptor expression after renal ablation

Angiotensin (ANG) II can be associated with gene expression regulation. Thus we studied the possible role of ANG II in the regulation of AT2 mRNA and protein expression. We utilized sham-operated renal ablation rats as well as renal ablation rats pretreated during the first 7 days of the development of renal damage with either the angiotensin-converting inhibitor ramipril, the AT1 receptor antagonist losartan, or the AT2 receptor antagonist PD-123319. Renal tissue was analyzed for histological changes and expression of AT2 receptor mRNA (by RT-PCR) and protein (by immunohistochemistry). To explore the physiological role of AT2 receptor overexpression in the development of renal damage, blood pressure, urinary protein excretion, and renal damage were evaluated. A time-dependent increase in the expression of AT2 receptor mRNA and protein was observed at 7, 15, and 30 days after renal ablation. Because these effects were already evident at day 7, the effects of ramipril, losartan, or PD-123319 were tested at...