Effect of Zinc on [H-3]Thymidine, [H-3]Uridine and [H-3]Glicine Incorporation in the Tissues of Rats Prenatally Exposured to Cadmium

On the the first day of pregnancy, Wistar rats were administered a single IP injection of either zinc sulfate (10.0 mg/kg) or saline. For the remainder of pregnancy, half the rats in each group then consumed filtered tap water while the other half consumed filtered tap water with 50 ppm of cadmium (Cd (CH3COO2). At eight weeks after birth both groups were injected with [H-3]thymidine (incorporated to DNA) or [H-3]uridine (incorporated to RNA) or [H-3]glicine (incorporated to protein) 1 mu Ci/kg IP. Four hours later rats were sacrificed by decapitation and parts of the brain and peripheral tissues were excised and examined for radioactivity in a liquid scintillation counter. Results were presented as a desintegration per minute - DPM/100 mg wet tissue weight, which expressed labeled substances incorporation. Prenatal cadmium exposure decreased incorporation of thymidine, uridine, and glicine in all examined tissues and organs. A single injection of zinc, preceding cadmium consumption, attenuated the effects of cadmium on incorporation of examined substances in peripheral organs, mostly liver, kidney, and pancreas. We concluded and confirmed our previous founding that a single zinc inection prior to cadmium exposure prevents some of its toxic effects on DNA, RNA, and protein synthesis in peripheral tissues of mammals.