Stimulation of NOS activity.

Evaluation of the NOS activity (A), nitrite/nitrate production (B), and caspase activity (C) in K562. Cells were treated with TRAIL (1 μg/mL) or with control His peptide for the indicated times. In panels A and C, data are expressed as percentage of His peptide–treated control cells. Data represent the means ± SDs of 4 independent experiments performed in duplicate.