Effect of intra-abdominal injections of 3'-methyl-4-dimethylamino-azobenzene on adenylic acid deaminase activity and nuclear ribonucleic acid metabolism of rat liver.

Abstract

The purpose of this study was to determine whether intraabdominal injections of 3′-Me-DAB caused increases in rat liver AMP deaminase activity. When rats were given single injections of 3′-Me-DAB at concentrations from 10 through 25 mg/100 gm body weight, enzyme activity was increased and the magnitude of the increase was related to the concentration of the dose administered. Single 3′-Me-DAB injections at 25 mg/100 gm body weight caused significant increases in 2 days, a doubling in 3 days, and in 6 days there was a maximum 3-fold increase. AMP deaminase activity was not appreciably affected by single injections of 4′-Me-DAB at 25 mg/100 gm body weight. Single injections of 3′-Me-DAB failed to cause significant changes in the diameter of rat liver nucleoli or nuclei after 10 days. The RNA from purified nuclei was subfractionated into a NNN fraction and a “nucleolar” fraction. The concentration of RNA in the NNN fraction was not changed by single injections of either 3′-Me-DAB or 4′-Me-DAB, but slight losses were seen in the “nucleolar” fraction of animals injected with 3′-Me-DAB. Incorporation of labeled orotic acid into both subfractions was inhibited by 3′-Me-DAB; the extent of inhibition was greater in the “nucleolar” fraction. Single injections of 4′-Me-DAB failed to affect incorporation of labeled orotic acid into either nuclear subfraction.