Significance of umbilical plasma concentrations of catecholamines and their metabolites in patients with term vaginal deliveries

: In an attempt to further clarify the physiological significance of Catecholamine (CA) s in the feto-placental unit, umbilical plasma concentrations of CAs and CA metabolites, 3-methoxy-4-hydroxy-phenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in cases of full-term vaginal deliveries by HPLC-ECD. Results were as follows. 1. Norepinephrine (NE) and epinephrine (E) levels were significantly higher in arterial than in venous plasma, but no significant arterio-venous differences were found with dopamine (DA) concentrations. 2. High concentrations of MHPG, DOPAC and HVA were demonstrated in both arterial and venous plasma. 3. DOPAC and HVA levels were significantly higher in arterial than in venous plasma, but no significant arterio-venous differences were noted with MHPG. 4. A significant positive linear relations hip was demonstrated between arterial levels of NE and MHPG as well as DA and DOPAC, DA and HVA. 5. Arterial plasma MHPG levels were correlated significantly with arterial plasma pH and pO2. These results suggest that, in the feto-placental unit, NE, E and DA turnover is increased at term vaginal deliveries, and NE and E secretion sensitively responds to fetal respiratory and metabolic states. In addition, it is suggested that the mechanism which controls the DA turnover is different from that of NE and E.