(Left) Western immunoblot analysis of eNOS protein (135-kDa) levels in cavernosal tissue of rats 24 h after administration of vehicle (lane 1), AdCMVβgal (lane 2), or AdCMVeNOS (lane 3). α-Actin (42-kDa) concentrations were used to control for sample loading. (Right) Densitometry analysis of eNOS protein (gel unit per milligram of protein) in rat corpus cavernosal tissue 1 day after administration of vehicle, AdCMVβgal, or AdCMVeNOS. n, number of experiments; ∗, response significantly different from AdCMVβgal (P < 0.05).