Postnatal expression of cytochrome P450 1A1, 2A3, and 2B1 mRNA in neonatal rat lung: Influence of maternal nicotine exposure

A critical factor contributing to the etiology or modification of respiratory disease is the ability of the lung tissue to activate or inactivate chemicals. In this study, the authors investigated the effect of maternal nicotine exposure during gestation and lactation on the expression mRNA of cytochrome P450 (CYP) CYP1A1, CYP2A3, and CYP2B1. Fetal rats were exposed to nicotine via maternal administration of nicotine (1 mg/kg body weight/day, subcutaneously); after birth, neonatal rats were exposed to nicotine via the mother's milk. Lung tissue of 1-, 7-, 14-, 21-, and 49-day-old rat pups were used. From weaning on postnatal day 21 up to postnatal day 49, the offspring received no nicotine. Using RNA dot-blot techniques, our results show that CYP mRNA expression in lung tissue increased with age after birth. Maternal nicotine exposure had no influence on CYP1A1 mRNA, but resulted in a marked increase in the expression of CYP2A3 mRNA and CYP2B1 mRNA. The higher levels of CYP2A3 mRNA and CYP2B1 mRNA were maintained after weaning.