EDN1 and isolated hemihyperplasia: Our hypotheses were tested to: 1) examine the effects of increasing episodes of neonatal IH on renal histopathology and morphometry (primary objective); 2) determine whether IH-induced renal damage is associated with Ang II, ET-1, and biomarkers of hypoxia and oxidative stress; and 3) identify the critical number of neonatal IH episodes that induce Ang II, ET-1, biomarkers of hypoxia and oxidative stress, and renal damage (secondary objectives).