Disposition of Intra-amniotically Administered Estriol-16-C14and Estrone-16-C14Sulfate by Women1

Abstract

Estriol-16-C¹⁴ (7 cases) and sodium estrone-16-C¹⁴ sulfate (6 cases) were administered intra-amniotically to pregnant women in their 12th to 20th weeks of gestation. Forty-five to 50 min later pregnancy was interrupted surgically. Various fetal tissues, the placenta and maternal urine were analyzed for radioactivity. An average of 6.6 % of the radioactivity administered as estriol appeared in the maternal urine within 72 hr as compared with 0.6% following the injection of sodium estrone sulfate. The fetal tissues contained approximately 10 times more radioactivity when estriol was administered than when sodium estrone sulfate was given. In both series, of the fetal tissues studied, the skin contained the highest concentration of radioactivity, the bulk of which was in a conjugated form, most probably as estriol-3-sulfate. However, in both series most of the radioactivity in the placenta and fetal membranes was present in an unconjugated form.