Treatment with apocynin, as well as DPI, attenuates intracellular GSH production and GCL activity by ICAM-1 cytoplasmic tail peptide. (A) GSH levels in response to AP-ICAM, AP, or vehicle plus apocynin (100 µM) versus the same treatments alone. (B) GCL activity in response to AP-ICAM, AP, or vehicle plus apocynin (100 µM) versus AP-ICAM treatment alone. (C) GSH levels in response to AP-ICAM, AP, or vehicle plus DPI (1 µM) versus the same treatments alone. (D) GCL activity in response to AP-ICAM, AP, or vehicle plus DPI (1 µM) versus the same treatments alone. n=5; #p<0.001, *p<0.01; experiments performed in quadruplicate.