Fig. (5). Erstressin downregulates iNOS activity in vivo Plasma nitrate/nitrite levels, an indirect measure of iNOS activity, in normal animals and animals challenged with bacterial lipopolysaccharide (LPS), with or without coadministration of erstressin (Es) dosed at 30 mg/kg via intraperitoneal injection. Drug and LPS were administered simultaneously and plasma nitrates were measured at 6 hours post-challenge. Each data point represents mean ± SE from 4-5 animals/ group, * p < 0.001.