Studies on RIA of 16 alpha-hydroxyestrone and its clinical application

16 alpha-hydroxyestrone (16 alpha-OH-E1) is an important intermediary metabolite in the biosynthetic pathway leading to estriol. No established routine method has been published to measure this steroid in the organism. A new RIA 16 alpha-OH-E1 method was developed and by using this method some interesting clinical data were obtained. Method: Rabbits were immunized with 16 alpha-OH-E1-3-CME-BSA to produce its antiserum. 16 alpha-OH-E1-3H was synthesized by incubating estrone-3H with the human fetal liver preparation and NADPH. As samples, peripheral blood of pregnant women, umbilical artery blood (UA), umbilical vein blood (UV) and amniotic fluid were collected. To each sample, 1000 dpm of 16 alpha-OH-E1-3H was added as a tracer, extracted with ether, and the extract was separated on TLC and LH-20. The 16 alpha-OH-E1 fraction was collected and used for RIA. Results: The 16 alpha-OH-E1 levels (ng/ml) in peripheral maternal blood of normal gestation before 11 weeks, 12-23 weeks, 24-36 weeks and after 37 weeks were 0.98 +/- 0.07 (mean +/- S.E.), 2.42 +/- 0.30, 4.76 +/- 0.42 and 5.49 +/- 0.98, respectively. A significant increase in the steroid titer was observed as gestational weeks advanced.(ABSTRACT TRUNCATED AT 250 WORDS)