A Radioimmunological Method for Oestrone

Abstract

A specific antiserum to estrone was used to develop a radioimmunoassay. No chromatographic separation step was included. A small amount of plasma (0.01-0.15 ml) was extracted once with diethyl ether. The method was used to estimate plasma levels of non-conjugated estrone in women during uncomplicated late pregnancy. The estrone plasma concentrations showed a gradual increase from a mean of 4 ng/ml in the 22nd wk to 11 ng/ml in the 41st wk. Great individual variations were found. No systematic changes of unconjugated estrone plasma concentrations were noticed during a 24-h period in late pregnancy. Short term studies revealed that large and rapid fluctuations may appear in the levels of unconjugated estrone during pregnancy.