Effects of nickel compounds on incorporation of [3H] thymidine into DNA in rat liver and kidney

In vivo incorporation of [3H] thymidine into DNA was determined in rats at 28 h after partial hepatectomy. Administration of nickel carbonyl (Ni(CO)4) at 2 or 4 h before sacrifice inhibited [3H] thymidine uptake into liver and kidney DNA. For example, in rats killed 4 h after i.v. injection of Ni(CO)4 (2 mg Ni/100 g), [3H]-labelling of liver DNA averaged 54 (SE +- 10% of controls (p<0.05), and [3H]-labelling of kidney DNA averaged 53 (SE +- 6)% of controls (p<0.01). Injection of NiCl2(2 mg Ni/100 g, i.m.) 4 h before death did not significantly affect [3H] thymidine uptake into liver DNA, but did inhibit [3H] thymidine uptake into kidney DNA (65 +- 6%, p<0.02). Binding of 63Ni to DNA in liver and kidney of rats killed 4 h after injection of 63Ni(CO)4 or 63NiCl2 ranged from 0.3 to 2.2 mol 63Ni/mol of DNA nucleotides. Ultracentrifugation of DNA on alkaline sucrose gradients did not reveal any differences between sedimentation profiles of hepatic DNA from Ni(CO)4-treated rats versus paired control rats