Neonatal lead toxicity and in vitro lipid peroxidation of rat brain.

Neonatal rats were given aqueous lead acetate intragastrically from d 2--20 of life at doses of 0, 25, 75, and 225 mg Pb/kg.d. Blood Pb concentrations on d 21 were (mean +/- SE) 27 +/- 4 (control), 150 +/- 26, 263 +/- 63, and 518 +/- 97 microgram/100 ml, respectively. Growth was significantly depressed only in animals given the highest dose of Pb (225 mg/kg.d). Hematocrits were significantly decreased by d21 at all doses of Pb. Malondialdehyde (MDA) formation in 750 x g (10 min) brain supernatants induced spontaneously by aerobic incubation at 37 degrees C was not altered by Pb on d 7 and 14, but a slight decrease was observed on d 21. The extent of MDA formation induced by enzymatically generated superoxide anion was not altered by Pb toxicity during the first 21 d of life. Addition of Pb to 750 x g (10 min) brain supernatants in vitro significantly decreased MDA formation at Pb concentrations of 10(-5) M and higher. These results show that the central nervous system toxicity of Pb in neonatal rats is not associated with accelerated in vitro lipid peroxidation of brain tissue.