Effect of isosorbide mononitrate (ISMN) treatment on soluble guanylyl cyclase (sGC) in rabbits. Protein expression of (a) sGC α1 subunit (P=0.2790) and (b) sGC β1 subunit in aortae of ISMN-treated rabbits measured by western blot densitometry. Neither the low-dose (ISMN-2) nor the high-dose (ISMN-200, each n=10, P=0.6900, analysis of variance (ANOVA)) group showed a significant change in protein expression. (c) Activity of sGC protein measured in pmol cGMP per mg protein per min in ISMN-treated rabbits. There was no significant difference among all three groups (n=6–7, P=0.0775, ANOVA). Results shown represent mean±s.e.m.