Time-dependent activation of Akt and eNOS paralleling PTEN phosphorylation by GTN. Representative Western blots showing PTEN phosphorylation (Ser 380), eNOS phosphorylation (Ser 1177 or 1179), and Akt phosphorylation (Ser 473) in (A) BAEC and (B) HMEC treated with vehicle or 500 nM GTN for the indicated amounts of time. Vehicle was added for 10 min in (A) and 15 min in (B). Results show rapid and sustained eNOS phosphorylation at the activation site Ser 1177, Akt phosphorylation at the activation site Ser 473, and PTEN phosphorylation at the inhibitory site Ser 380 by 500 nM GTN. Band intensities for phosphorylated eNOS in BAEC and for the experiments performed with HMEC were quantified using ImageJ and the values are reported as density units relative to control; *P<0.05, **P<0.01.