[The effect of sodium nitroprusside and nitro-containing vasodilators on rat liver microsomal mono-oxygenases].

: It has been shown in vitro that sodium nitroprusside (SN) causes a concentration-dependent suppression of the enzymatic activity of aminopyridine demethylase-APDM(IC50 = 1.86 x 10(-4) M) and ethoxycoumarin O-deethylase-ECOD(IC50 = 1.46 x 10(-4) M) in hepatic microsomes of Wistar rats, which is related to different isoforms of cytochrome P-450. The inhibiting effect of other nitro compounds (nitroglycerin and isosorbide dinitrate) in relation to APDM is less marked than that of SN. These compounds have practically no effect on ECOD activity. It is assumed that the degree of the inhibiting effect of SN, nitroglycerin, and isosorbide dinitrate is connected with the mechanism of NO release.