Nickel Carbonyl Inhibition of 14 C-Orotic Acid Incorporation into Rat Liver RNA ∗

Abstract

Summary

Nickel carbonyl, a metallic carcinogen inhibited ¹⁴C-orotic acid incorporation into liver RNA. Forty min after an ip injection of ¹⁴C-orotic acid, the mean specific activity of RNA from livers of control rats was 318 (SD, ± 133) μmoles of ¹⁴C/mole of ribose. In rats which also received an intravenous injection of nickel carbonyl (2.2 mg of Ni/100 g) 24 hr before sacrifice, the mean specific activity of liver RNA was 81 (SD, ± 23) μmoles of ¹⁴C/mole of ribose (p vs controls = <0.01). The incorporation of ¹⁴C-orotic acid into liver RNA was not significantly affected by injection of phenobarbital (10 mg/100 g, ip) 20 hr before sacrifice. This work supports the hypothesis that nickel carbonyl inhibits the synthesis of hepatic RNA.