Possible Application of Chemical Reactions in the Determination of Pregnancy. ∗

It is generally conceded that the reaction of the Ascheim-Zondek test depends upon the presence of a hormone in the urine of the pregnant woman. This hormone is believed to be either antuitrin, from the pituitary gland, or the so-called antuitrin-like hormone, from the placenta. Any chemical test that would be specific for either of these hormones would in all probability constitute a satisfactory test for pregnancy, which, if the test could be made simple enough, would have great advantages over the biological tests now in general use.

We have found that under carefully controlled conditions, that is, in a solution neutral to brom thymol blue, the commercial preparation of antuitrin will invariably reduce the oxidation-reduction dye, o-chlorophenol indolphenol, from blue to pink. The antuitrin-like hormone, commercial antuitrin S, will not cause this reduction, but both it and the antuitrin will reduce 1-naphthol-2-sulfonate indophenol in an alkaline solution. These reactions can be obtained in water solution or with non-pregnant urines to which comparatively large amounts of the commercial preparations have been added. This test, simple and definite, gives promise of an excellent test for pregnancy.

In its practical application, however, it is necessary to extract the very small amounts of the hormone present in the urine before applying the test since otherwise it may be masked by interfering substances. In the case of pathological urines, also, other proteins, unless previously removed, may give a similar reaction. It is in this extraction that we have encountered the greatest difficulties in the way of the method. It has not yet been worked out to a degree of accuracy that will permit the application of the test in a practical way. After trying, however, the various methods found in the literature for the extraction of these hormones, we have devised from them, with some variations introduced by us, a method of extraction that permits us to check the results of the Ascheim-Zondek test in a great majority of the cases.