Effects of exposure to lead on social behaviour in the laboratory mouse

Ethological analysis has been employed to study the behavioural effects produced by exposure of mice to lead salts from infancy. Mother mice of the treated group received 0.1% lead acetate as their sole drinking fluid within 24 h after the birth of their litters and the offspring received this fluid from weaning. At 8 weeks, encounters between pairs of unfamiliar mice from the same treatment group and of the same sex were examined by ethological techniques. The frequency and duration of social and sexual investigation was found to be significantly lower in lead-treated mice of both sexes than in their controls. In lead-treated males, agonistic behaviour was also reduced. These effects were due to a reduction in the frequency of several postural elements within each of the categories. Body weight gain was not affected by treatment with lead at this dose level and there were no signs of hyperactivity. The average lead content of the brains was found to be 2.45 nmol/g in the control group and 4.38 nmol/g in the group given lead acetate.