Estimation of Rates of Production and Transfer of Hormones in Pregnancy

Abstract

Although the level of estrogens, particularly that of estriol, in the urine of the mother is a useful index of fetal viability, little can be learned from it about the secretion and metabolism of hormones made by the fetus and the placenta. Estriol is the end product of a complex array of processes involving the secretion by the fetal and maternal adrenals of neutral precursors such as dehydroisoandrosterone and its sulfate, their hydroxylation at C-16 by the liver and other organs, and, finally, aromatization by the placenta. The estrogens formed in the placenta enter partly into the maternal and partly into the fetal circulations and undergo further metabolism prior to their excretion in the urine. If we are to evaluate the role of hormones in the development of the fetus and to diagnose and treat abnormal conditions of the intrauterine patient, insight must be gained into the processes of synthesis and metabolism. Therefore, methods must be developed to measure rates of secretion and metabolism of the hormones made by the fetus and the placenta. This presentation describes some of our efforts to develop methods to measure rates of entry of steroids into the maternal and fetal circulations as well as to measure rates of exchange between these circulations.

This work was supported by Grant HD02996 and AM-00110 of the N.I.H. of the U.S.P.H.S.