Abstract Paraquat (1,1’-dimethyl-4,4’-bipyridyl dichloride) is an herbicide widely used worldwide and officially banned in Brazil in 2020. Kidney lesions frequently occur, leading to acute kidney injury (AKI) due to exacerbated reactive O2 species (ROS) production. However, the consequences of ROS exposure on ionic transport and the regulator local renin-angiotensin-aldosterone system (RAAS) still need to be elucidated at a molecular level. This study evaluated how ROS acutely influences Na+-transporting ATPases and the renal RAAS. Adult male Wistar rats received paraquat (20 mg/kg; ip). After 24 h, we observed body weight loss and elevation of urinary flow and serum creatinine. In the renal cortex, paraquat increased ROS levels, NADPH oxidase and (Na++K+)ATPase activities, angiotensin II-type 1 receptors, tumor necrosis factor-α (TNF-α), and interleukin-6. In the medulla, paraquat increased ROS levels and NADPH oxidase activity but inhibited (Na++K+)ATPase. Paraquat induced opposite effects on the ouabain-resistant Na+-ATPase in the cortex (decrease) and medulla (increase). These alterations, except for increased serum creatinine and renal levels of TNF-α and interleukin-6, were prevented by 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (tempol; 1 mmol/L in drinking water), a stable antioxidant. In summary, after paraquat poisoning, ROS production culminated with impaired medullary function, urinary fluid loss, and disruption of Na+-transporting ATPases and angiotensin II signaling. 1,1dimethyl4,4bipyridyl 11dimethyl44bipyridyl dimethylbipyridyl 1,1 dimethyl 4,4 bipyridyl 4 dichloride 2020 occur AKI (AKI O (ROS However reninangiotensinaldosterone renin aldosterone RAAS (RAAS level Na+transporting Natransporting Na+ transporting Na 20 (2 mg/kg mgkg mg kg ip. ip . ip) 2 h Na++K+ATPase NaKATPase Na++K+ ATPase K activities IItype type receptors factorα factor α TNFα, TNFα TNF , (TNF-α) interleukin6. interleukin6 interleukin 6. 6 interleukin-6 Na++K+ATPase. ATPase. ouabainresistant ouabain resistant Na+ATPase NaATPase decrease (decrease increase. increase (increase) alterations interleukin6, 6, 4hydroxy2,2,6,6tetramethylpiperidin1oxyl 4hydroxy2266tetramethylpiperidin1oxyl hydroxytetramethylpiperidinoxyl hydroxy 2,2,6,6 tetramethylpiperidin oxyl tempol (tempol mmolL mmol L water, water water) antioxidant summary poisoning function signaling 1dimethyl4 4bipyridyl 11 1, 44 4, 202 ( NaK Na++K (TNF-α interleukin- (increase 4hydroxy2 6tetramethylpiperidin1oxyl 2266 2,2,6, 1dimethyl 4hydroxy tetramethylpiperidinoxyl 226 2,2,6 22 2,2, 2,2 2,