THE ISOLATION OF (r-DIHYDROTHEELIN FROM HUMAN PREGNANCY URINE

The quantitative determination of urinary estrogens is being applied widely as a research procedure in the study of normal and pathological conditions. Most investigators have limited their work to the estimation of total estrogenic potency, although it has been known for some time that the urine of pregnant women contains at least two estrogenic compounds, theelin and theelol. Experiments upon rabbits by Pincus and Zahl (1937) indicated that theelin is converted to thee101 by the action of progesterone upon the rabbit uterus. It appeared, therefore, that the separate determination of theelin and thee101 in the urine of women might provide a gage of progestin as well as estrogen metabolism, and a study (Smith, Smith, and Pincus, 1938) in which this procedure was carried out during a normal menstrual cycle and a pregnancy gave evidence in support of the supposition. Further studies (Smith and Smith, 1938, 1940) have confirmed this observation and have demonstrated that the separate determination of urinary cst,rogens yields much more information than may be gained by the determination of total estrogenic potency alone. In the interpretation of these data it becomes of importance to know whether or not any estrogens other than theelin and theelol are contributing significantly to the estrogenic potency of the separate fractions. Comparison of colorimctric with bioassay