Lead exposure, environmental temperature, nesting and consummatory behavior of adult male mice of two ages.

Both younger (60-day-old) and older (365-day-old) male, heterogeneous stock mice were exposed to either a 0.5% lead acetate solution or water as their sole source of fluid for four weeks prior to testing their nest building and consummatory behavior in a temperature chamber. During the three weeks in the temperature chambers lead and water maintenance were continued, and fluid and food consumption, body weight and nest building were monitored. Temperature in the chambers was 21 degrees C during the first week, then reduced to 5 degrees C during the second week, and returned to 21 degrees C in the last week of testing. In general, younger animals responded more rapidly and more intensely than older mice to changes in temperature as reflected in consummatory behavior, but lead ingestion decreased the magnitude of the change in fluid intake. Lead ingestion also altered the pattern of change in food ingestion of older mice as a function of the reduced temperature challenge. The complexity of nests built increased when temperatures were lowered from 21 degrees C to 5 degrees C, but this measure was unaffected by lead ingestion or age.