NOS2 and serum lipopolysaccharide activity: The effect of endotoxemia on Oct-mediated tubular secretion has been previously put forth by Heemskerk and colleagues, who demonstrated that aminoguanidine, an inhibitor of the inducible nitric oxide synthase (iNOS), rescued the tubular secretion of Rhodamine 123 and the protein expression of oct1 and oct2, but not that of their mRNA, in the kidney of Wistar Hannover rats injected with LPS (34).