ZD 7155

ZD 7155 is an AT1R selective antagonist with renal function modulating activity. The effects of ZD 7155 on glomeruli and tubules were measured in 1- (N = 9) and 6-week-old (N = 13) lambs. Pretreatment with ZD 7155 after L-NAME infusion did not alter glomerular function in 1- or 6-week-old lambs. During postnatal development, Ang II modulates the effects of NO on electrolyte handling via AT1R and AT2R. In 6-week-old lambs, selective inhibition of AT1R and AT2R increased the excretion of Na+, K+, and Cl-. In 6-week-old lambs, pretreatment with ZD 7155 and PD 123319 followed by the addition of L-NAME increased urine flow rate by 200%, free water clearance by 50%, and decreased urine osmolality by 40%. The same trends of changes in these variables were also observed when L-NAME was added to ZD 7155 or PD 123319, although to a lesser extent.