Method of Preparing Mice for Quantitative Determination of Urinary Estrogen. ∗

The methods of biological assay for urinary estrogen in use at the present time are dependent upon the production of estrus in a castrated mouse or rat. Various modifications of the original Allen-Doisy test have been used, such variations being single or multiple injections of either aqueous, glycerol, or oily extracts into castrated or immature normal mice or rats. Methods utilizing male animals and fish have not as yet proved of any great value for quantitative purposes.

Chemical methods for the determination of urinary estrogen have been proposed by Kober, 1 Cohen and Marrian, 2 David, 3 Cartland et al., 4 Schmulovitz and Wylie, 5 , 6 and Pincus et al. 7 Chemical tests based on color changes in the test tube and comparison with standards are preferable to biological tests. The disadvantage of chemical tests is chiefly their inapplicability to the estimation of estrogens in the urine of non-pregnant women. For this purpose we must, for the present, still resort to biological means.

A biological test for urinary estrogen must be for the biological activity of all the estrogenic substances present in the urinary extract. The test cannot be specific for, or differentiate between, different forms of the hormone. The advantage of the biological method is its ability to demonstrate very small amounts of estrogenic hormone in the presence of inactive impurities. The disadvantages are the troublesome time consuming procedures and the necessity of maintaining a supply of test animals. The greatest disadvantage is the source of error and variation in methods. More than a 4000% variation can he demonstrated in the procedures 3 now used.

This paper is presented in an ctiort to decrease the large percent of error and variation. Our test animal I)!- choicc has ken the castrated adult female mouse. just as chemically piire hornic me ior assay is tested against a knon-n ctantlartl hormone.