Fig. 4. (  A ) Representative immunoblot analysis of protein kinase C (PKC) isoforms including PKC-α, PKC-δ, PKC-ϵ, and PKC-ζ in normal (N) and diabetic (D) cardiomyocytes. Actin was used as a control for protein loading. Positive control = rat brain lysate (RBL). (  B ) Immunoblot analysis of constitutive nitric oxide synthase (cNOS) and inducible NOS (iNOS) in normal (N) and diabetic (D) cardiomyocytes.