The metabolic response of fetal and neonatal lung tissue to maternal nicotine exposure (0.25 and 1.0 mg/kg body weight/day) was investigated. White virgin female rats (Wistar) of 200-250 g were used. The rats were mated overnight and were afterwards randomly assigned to control and experimental groups. The experimental group was subdivided into two groups. One group received nicotine during pregnancy and lactation. The second group received nicotine only during lactation. The suckling rats were killed 24 h after the last dose of nicotine was administered to the mother. The lung tissue was surgically removed and the in vitro utilization of exogenous glucose and endogenous glycogen determined. Lactate production was also determined to assess glycolytic activity. Maternal nicotine administration during pregnancy and lactation stimulated total glucose turnover by 21.6 and 86.4% respectively but suppressed glycogenolysis (32.7%) and glycolysis by 24.6% (p less than 0.01). Nicotine administration during lactation only enhanced total glucose turnover by 19.1% (p less than 0.01) and glycogenolysis by 30% (p less than 0.01) but inhibited glycolysis by 25.8%. After 4 weeks of nicotine withdrawal when the rats were 7 weeks old, glycogenolysis and glycolysis of those animals exposed to nicotine via the placenta and mother's milk were still inhibited to the same extent as during exposure. Glycogenolysis and the glycolytic flux of lung tissue of rats exposed to nicotine via mother's milk only returned to normal.(ABSTRACT TRUNCATED AT 250 WORDS)