Gilbert's jaundice. Current clinico-nosographical, physiopathological and therapeutic aspects. Note II. The phenomenon of enzyme induction at the level of the liver

After a brief survey of the various modifications that may be encountered by drugs through the work of systems that detoxify the liver cell, attention is given to the problem of enzymic induction. The latter is the result of derepression of a gene that codes for a given enzyme; at the molecular level, derepression takes place when the substrate, by changing the tertiary structure of the repressor, brings about its detachment from DNA: in this way, RNA-polymerase is made capable of synthesising the corresponding mRNA. The inducing activity of phenobarbitone, a drug employed classically in the management of Gilbertian forms, must be substantially attributed to an increase in the synthesis of microsomial proteins, as shown by studies with labelled amino acids.