Table 3. Both NaHS and GYY4137 reduced the activity of purified PDE 5A (n = 8, mean ± SEM).

group	5′- GMP (μmol/L)	P
Control	25.93 ± 1.62
NaHS 3 μmol/L	15.96 ± 0.31*	0.004
NaHS 50 μmol/L	15.20 ± 0.63*	0.002
NaHS 300 μmol/L	14.80 ± 0.70*	0.001
NaHS 50 μmol/L +DTT	19.81 ± 0.77##	0.006
GYY4137 200 μmol/L	11.36 ± 0.39*	0.0003

DTT: 2 mmol/L; ^*P < 0.01 vs control group; ^##P < 0.01 vs NaHS 50 μmol/L group.