Altered uptake and biological half-lives of 65Zn on arsenic exposure--modulation by zinc treatment.

The present study revealed the effects of zinc on the biokinetics of (65)Zn in rats following arsenic intoxication. The animals were segregated into four groups: group I--untreated controls, group II--arsenic treated (100 ppm as NaAsO(2) in drinking water), group III--zinc treated (227 mg ZnSO(4) per liter drinking water), and group IV--arsenic + zinc treated. Each rat was injected intraperitoneally with 1.85 MBq radioactivity of (65)Zn following 3 months of different treatments, and the radioactivity was determined using a suitably shielded scintillation counter. Arsenic treatment showed a significant increase in the fast component (Tb(1)) of the biological half-life of (65)Zn in liver, which remained unaltered in the whole body. Furthermore, arsenic treatment decreased significantly the slow component (Tb(2)) in the whole body, which remained unchanged in the liver. However, zinc supplementation to arsenic-treated rats normalized Tb(1) in the liver, but caused no change in Tb(2) in the whole body. Furthermore, the uptake values of (65)Zn were significantly increased in the liver, brain, kidney, and intestine following arsenic treatment, and the values in the liver and brain were decreased by zinc. Hence, zinc plays a significant role in regulating the biokinetics of (65)Zn in the liver and the whole body of arsenic-intoxicated rats.