Desoxycorticosterone in normal pregnancy. III. Evidence of a fetal source of desoxycorticosterone.

The source of the markedly increased secretion of desoxycorticosterone (DOC) in pregnancy has not been precisely defined. Earlier studies indicated that elevated DOC does not arise from the maternal adrenal glands. The previously observed steep gradient between fetal and maternal DOC and DOC sulfate concentrations seemed to point to a fetal source. A recent study suggests that Doc may also be derived from extra-adrenal conversion of maternal progesterone. The present investigation documents a lack of synchrony between maternal diurnal plasma cortisol and DOC patterns. Not only were the previous observations of steep gradients of DOC and DOC sulfate between fetal and maternal circulations confirmed, but also the finding of extremely high urinary excretion of DOC sulfate indicated that the sulfurylated steroid passes across the placenta. A direct linear correlation was noticed between cortisol and DOC in amniotic fluid. These observations suggest that the increased DOC arises from within the fetoplacental unit but do not rule out a maternal source.