Oxidative stress induces cardiac myocyte apoptosis. At least some effects are probably mediated through changes in gene expression. Using Affymetrix arrays, we examined the changes in gene expression induced by H2O2 (0.04, 0.1, and 0.2 mM; 2 and 4h) in rat neonatal ventricular myocytes. Changes in selected upregulated genes were confirmed by ratiometric RT-PCR. p21(Cipl/Wafl) was one of the only two genes upregulated in all conditions studied. Of the heat shock proteins, only Hsp70/70.1 was induced by H2O2 with no change in the expression of Hsp25, Hsp60 or Hsp90. Heme oxygenase 1 was also potently upregulated, but not heme oxygenases 2 or 3. Of the intercellular adhesion proteins, syndecan-1 was significantly upregulated in response to H2O2, with little change in the expression of other syndecans and no change in expression of any of the integrins studied. Thus, oxidative stress, exemplified by H2O2, selectively promotes the expression of specific gene family members. (C) 2003 Elsevier Inc. All rights reserved.