A, Similar levels of NOS activity after 3 weeks of TAC between β3−/−-TAC and WT-TAC by arginine-citrulline conversion. B, Decreased total NOS activity in β3−/−-TAC vs. WT-TAC after 9 weeks of TAC. C, No differences in eNOS expression levels. D, Enhanced eNOS activation shown by increased peNOS/eNOS ratio in WT-TAC, but no response in β3−/−-TAC. E, nNOS is elevated in β3−/−-TAC vs. β3−/− and WT-TAC. F, iNOS is elevated in β3−/−-TAC vs. β3−/− (P<0.01), although no different than WT-TAC. *P<0.05 vs. baseline, †P<0.05 vs. WT-TAC by post-hoc analysis.