Incorporation of [3H]uridine and [3H]glycine in the brain of rats prenatally exposure to cadmium

Numerous studies have demonstrated that exposure of mammalians, including humans to inorganic cadmium, result in a cascade of toxic effects. The developing mammalian brain is particularly more sensitive to cadmium then the adult brain, being affected both morphologically and neurochemically. Uridine is a precursor of RNA, and the intensity of its incorporation in tissue represents the rate of RNA and protein synthesis. Glicine is an important aminoacid, an element of many proteins and enzymes in mammalian organism. On the first day of pregnancy, Wistar rats were divided into two groups. First, control consumed filtred tap water while other half consumed filtred tap water with 50 ppm cadmium (CdCH3COO2). At eight weeks after birth both groups were injected with [3H]uridine (incorporated to RNA) or [3H]glycine (incorporated to protein) 1 μCi/kg IP. Four hours later rats were sacrificed by decapitation and parts of the brain were excised and examined for radioactivity in liquid scintillation counter. Results were presented as a disintegration per minute (DPM)/100 mg wet tissue weight, which expressed labeled substances incorporation. Prenatal exposure with cadmium significantly decreased [3H]uridine incorporation in all examined parts of the brain (frontal cortex, striatum, thalamus with hypothalamus, pons, hippocampus, cerebellum). Neonatal exposure rats to cadmium decreased incorporation of the [3H]glycine in frontal cortex, thalamus with hypothalamus, pons and cerebellum. From above we concluded and confirmed that prenatal exposure with cadmium exert a toxic effect on RNA and proteins synthesis in the brain of developing rats.