Diamine oxidase activity induction in regenerating rat liver

The synthesis and turnover of diamine oxidase (EC 1.4.3.6) activity was studied in regenerating rat liver after partial hepatectomy using inhibitors of protein and RNA syntheses. The administration to animals of cycloheximide or actinomycin D prevented the increase in diamine oxidase activity normally observed during the first hours after hepatectomy. The study of the turnover rate of diamine oxidase with cycloheximide demonstrated that the half-life of this enzyme was about 15 h in normal and regenerating liver. These results suggest that the rise in diamine oxidase activity in regenerating rat liver was due to the synthesis of new enzyme rather than to a lengthening of its turnover.