Dose response relationships during perinatal lead administration in the rat: a model for the study of lead effects on brain development.

Pregnant rats were dosed with 300, 600, 1000, 2000, 3000 or 4000 ppm inorganic lead through their drinking water during pregnancy and during lactation until 21 days post partum. An effect on live litter size was noted at the higher doses as was an increased tendency for sperm positive females to fail to produce a litter. Dose related responses were seen in the offspring for brain weight, body weight, body length and blood lead at birth and at age 21 days. In neonates from the dose groups above 1000 ppm Pb these 3 indices of growth indicated that there was an effect of lead on nutrition. The 300 ppm, 600 ppm and 1000 ppm dose groups showed no significant dose related effects for body length or brain weight and only slight effects on body weight. These low dose groups gave average blood lead values of 39.8 micrograms/100 ml blood, 54.6 micrograms/100 ml blood and 85.4 micrograms/100 ml blood respectively in the 21-day old neonates. These values correspond to blood lead values in children with so called "subclinical lead poisoning" and we suggest the use of this regime as a model to investigate effects of lead on development of the nervous system.