In vitro stimulation of microsomal diethyl nitrosamine deethylase activity by vitamin K3 (menadione).

ABSTRACT

Vitamin K3 (menadione) has been found to stimulate diethyl nitrosamine (DEN)-deethylase activity in rat liver microsomes. The vitamin also takes care of the inhibitory effect of the anaerobic conditions as well as those of cytochrome poisons like sodium azide and sodium cyanide, possibly through production of active oxygen species. The enzyme was also stimulated by H2O2 and SOD and inhibited by catalase, thereby suggesting that H2O2 or some derivatives of it may be the active oxygen species involved in the reaction.