Abstract
1. Nipradilol (NP) was metabolized mainly in liver and denitrated and/or hydroxylated metabolites were formed. NP was not metabolized in heart or lung, and was stable in blood.
2. Denitration of NP was catalysed mainly by glutathione-dependent organic nitrate reductase in liver cytosol, and the hydroxylation was catalysed by liver-microsomal enzymes.
3. Denitration activity for NP was far lower than that for nitroglycerol and isosorbide dinitrate with liver homogenates of several animal species.
4. A marked species difference was found in the denitration activity for NP; dog liver was especially low compared with rabbit, rat and mouse liver.