Clearance of 3H-dopamine from the amniotic fluid in the rhesus monkey

Previous studies have suggested that dopamine is the major catecholamine in the amniotic fluid; however, there are few data available concerning the metabolism of this hormone in the amniotic fluid compartment. With the use of acute 3H-dopamine injection studies into the amniotic sac of pregnant rhesus monkeys, the dopamine half-life was observed to be 29 minutes, the amniotic fluid volume was 113 ml, the metabolic clearance rate was 164 ml/hr, and the calculated production rate was 436 ng/hr. The biphasic pattern of dopamine clearance from this compartment suggests that it is cleared from the amniotic sac by mechanisms similar to those used in the intravascular compartment.