Contribution of Estriol to Total Urinary Estrogens during Pregnancy

Abstract

Estriol accounts for an average of 74% of the principal Kober-positive steroids in the urine of 13 women during uncomplicated pregnancies. This proportion is independent of the stage of pregnancy, from 20 weeks until term. The average ratio of estriol to ring-D α-ketols (mainly 16α-hydroxyestrone and 16-ketoestradiol-17β) is about 5:1 over the same period. In 17 pregnant women with diabetes, urinary estriol averaged 63% of the "total steroids" during a similar period, and the average ratio of estriol to ring-D α-ketols was 3:1. The quantitative importance of these ketolic steroids may introduce a problem in deciding whether to measure estriol or "total estrogens" when evaluating fetal viability in complicated pregnancies.

Maternal Serum Hpl Levels in Normal and Complicated Pregnancy as an Index of Placental Function

“…It is not specific to oestriol but measures total conjugated oestrogens. Becaus 2 oestriol forms approximately 74 per cent of total oestrogen excration during late pregnancy (Hobkirk et al, 1970), @he name of oestriol has been used in the present study far brevity. The maximum time interval berween HPL and oestriol samples was not longer than two days.…”

Steroid metabolism in the cat. Biliary and urinary excretion of metabolites of [4-14C]oestradiol

“…There are at least two possible explanations for these sex differences. In man, oestrone is excreted mainly as its sulphate (Hobkirk, Nilsen & Blahey, 1969), whereas oestradiol and oestriol are excreted as glucuronides or as compounds doubly conjugated with both glucuronic acid and sulphuric acid (Adlercreutz & Luukkainen, 1967). Species and sex differences in metabolism and excretion of a wide range of steroid hormones and their metabolites are well established (Rao & Taylor, 1965a;Sandberg et al 1967).…”