Effects of pentaerythrityl tetranitrate (PETN) treatment on soluble guanylyl cyclase (sGC) in mice. Protein expression of (a) sGC α1 subunit (P=0.0961, n=8) and (b) sGC β1 subunit (P=0.3709, n=8, analysis of variance (ANOVA)) in lungs of PETN-treated mice measured by western blot densitometry. None of the groups treated with different doses of PETN showed a significant change in protein expression. (c) Activity of sGC protein measured in pmol cGMP per mg protein per min in PETN-treated mice. There was no significant difference among all four groups (P=0.6348, n=7, two-way ANOVA). (d) NO-dependent vasorelaxation in aortic rings of PETN-treated mice induced by the NO-donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP). Again, there was no significant difference between the groups (P=0.8865, two-way ANOVA). All values represent mean±s.e.m.