[The effects of nicotine on the synthesis and secretion of surfactant in the rabbit fetal lung].

The effects of nicotine administration on the synthesis and secretion of surfactant in the rabbit fetal lung were studied by measuring phosphatidylcholine (PC) and phosphatidylglycerol (PG) in the fetal lung tissue and amniotic fluid. The concentrations of both PC and PG in the lung tissue were decreased by administering nicotine to the mother. On the other hand, the concentrations of PC and PG in the amnniotic fluid were not altered by nicotine administration. Moreover, the PG/PC ratio in the amniotic fluid of the nicotine group was similar to that of the control group. The plasma catecholamine levels were elevated in the growth retarded fetuses from nicotine-treated mothers. These findings indicated that the administration of nicotine to the mother suppressed the synthesis of surfactant in the fetal lung but enhanced the secretion of surfactant to the alveolar cavity, probably via the stimulation of beta-receptor by catecholamine, and that the biochemical maturity of the surfactant was not altered by the administration of nicotine to the mother. The results of the present study might provide basic information to help to understand the clinical experiences reported by others i.e. that in the newborn from a smoking mother, respiratory distress occurred less frequently than in those from non-smokers.