Effect of NOS inhibitors on APAP-induced toxicity in freshly isolated hepatocytes. Hepatocytes were incubated with APAP (1 mM) for 2 h, washed to remove APAP (arrow), and subsequently incubated in media alone (2–5 h) (▼). Control hepatocytes were incubated in media alone for 2 h, washed, and subsequently incubated in media alone (2–5 h) (●). Following washing to remove APAP, some hepatocytes (A) were incubated with the general NOS inhibitor L-NMMA (1 mM) (◆) or the nNOS inhibitor 7-nitroindazole (10 μM) (■) (2–5 h). Following washing to remove APAP, other hepatocytes (B) were incubated with the iNOS inhibitors L-NIL (1 mM) (■) or SAIT (1 mM) (◆) (2–5 h). Aliquots were taken and toxicity determined by ALT release. Samples (n = 3 from separate mice) which significantly increased from the same 2 h incubation are indicated by * (p ≤ 0.05).