[Serotonin metabolism in normal pregnant women and fetus].

To evaluate serotonin (5-HT) metabolism in normal pregnant women and their fetuses, plasma free 5-HT, 5-hydroxyindoleacetic acid (5-HIAA). Tryptophan (TRP) and platelet free 5-HT content were determined by HPLC with electrochemical detection. Plasma free 5-HT and TRP concentrations and platelet 5-HT content in pregnant women did not change during pregnancy. In contrast, plasma free 5-HIAA increased after 30 weeks of gestation and reached its peak at 37 weeks. 5-HT, 5-HIAA and TRP concentrations in umbilical cord plasma were significantly higher than in maternal plasma. However, platelet 5-HT content in the fetus was significantly lower than in the mother. No significant correlation was found between 5-HT concentrations in maternal and cord plasma. However, a significant correlation was found between 5-HIAA, concentrations in maternal and cord plasma. The total 5-HT/TRP ratio in cord blood was significantly lower than in the maternal vein. The 5-HIAA/5-HT ratio in cord plasma was markedly higher than in maternal plasma. In conclusion, we demonstrated the patterns of plasma free 5-HT, 5-HIAA, TRP and platelet 5-HT concentrations in normal pregnant women and their fetuses. Furthermore, rapid 5-HT metabolism in the fetus was suggested.