Plasma Levels of Neopterin and Biopterin in the Umbilical Vessels and the Maternal Vein

Abstract

Tetrahydrobiopterin (BH4) is a highly bioactive pterin required for nitric oxide synthase and monooxygenases of aromatic amino acids, and is involved in the synthesis of nitric oxide, catecholamines and Serotonin. Although these functions imply that pterin metabolism plays critical roles in human development, the intrauterine metabolism is unclear. To elucidate the pterin metabolism in the human feto-placental unit, blood was obtained from the umbilical artery and vein, and the maternal vein, and plasma biopterin and neopterin concentrations were analyzed by the high-performance liquid chromatography method. To clarify the effect of labor, data was also compared between the transvaginal delivery (TV) and the caesarean delivery (CS). The levels of biopterin and the neopterin, and neopterin/biopterin ratio were higher in the fetal plasma than in the maternal plasma. Biopterin levels in the umbilical artery were higher than those in the umbilical vein. There were significant correlations in either biopterin or neopterin between the fetal plasma and the maternal plasma. There was no significant difference in the fetal pterin levels between TV and CS. The results suggest the stimulated BH4 synthesis in the fetoplacental unit, the independent homeostasis of the fetal pterin metabolism, and the possibility of dynamic movements of pterins among the fetus, the placenta and the mother.

Keywords

• tetrahydrobiopterin
• placenta
• fetus
• biopterin
• neopterin