In contrast with losartan, sparsentan-treated animals demonstrated greater AA/EA diameters and higher SNGFR in physiological as well as FSGS disease conditions (Figures 1 and 4), suggesting that ET-1 is an important contributor to the regulation of glomerular hemodynamics in the healthy kidney and a player in FSGS pathogenesis. This evidence concerns the gene EDN1 and focal segmental glomerulosclerosis.