Einfluß des carcinogenenN-Nitroso-niorpholins auf die Induzierbarkeit von Tryptophan-Oxygenase und Tyrosin-2-Oxoglutarat-Transaminase in der Rattenleber

Abstract

Biochemically measureable changes, prior to discernible histological deterioration of the rat liver cell were studied during experimentally induced carcinogenesis by N-nitrosomorpholine. The substrate-induction of tyrosine-2-oxoglutarate transaminase was reduced after about 20 days of oral administration of N-nitrosomorpholine and that of tryptophan-oxygenase after about 70 days. The cortisone induction of both enzymes was uninfluenced. It can be concluded from the experiments with actinomycin D, that the synthesis of messenger-RNA, during the substrate induction of both these enzymes, is reduced in pre-cancerous liver,.