3H-dopamine clearance from the intravascular compartment of the maternal and fetal rhesus monkey

The clearance of epinephrine and norepinephrine from the intravascular compartment has previously been demonstrated in both pregnant and nonpregnant models. With the use of the pregnant rhesus monkey, this study describes the clearance of dopamine from the fetal and maternal intravascular compartments. In both, the dopamine clearance was biphasic with an initial half-life of 1.5 minutes in fetal blood and 1.0 minute in maternal blood. These studies also confirmed that dopamine does not significantly cross the placenta in an intact form. These observations are consistent with those made for the other two major catecholamines.