Bioassay of Steroid Hormones

Abstract

Various bioassay methods for the steroid hormones are now available which have been subjected to statistical analysis. Some methods need additional study so that the statistical character-istics may be better known. This is true for most of the progesta-tional assays, the levator ani muscle test, and certain adreno-cortical assays such as the anti-inflammation test, the in vitro lymphocytotoxic test, and the electroshock threshold test. In general the sensitivity of the methods is adequate for the study of new compounds and steroids in urine. However, the low concns. of steroid hormones in blood and tissues still demand the develop-ment of methods with sensitivities 10-100 times those now avail-able. Analysis of the various assay methods has avoided the complex question of the biological activity of mixtures of steroids or steroids in combination with non-steroidal substances. Evi- dence at hand now indicates that activity of a given steroid may be significantly altered when admixed with other substances. Modification of activity of a steroid may be produced by the following conditions: steroid actions may be modified by nonsteroidal substances; steroid actions may be modified by other biologically active steroids; steroid actions may be modified by steroids without any other known activities. When steroid assay methods are employed for assays involving mixtures, these facts must be considered. Finally, when one employs local tests such as a comb inunction technique for androgens, an intravaginal assay for estrogens, or an intrauterine method for progesterone, the factor of pro-hormones must be considered. Excellent evidence at hand indicates that the pro-estrogen theory of Emmens may be stated in a general way for all steroid hormones. This means that a substance may prove to be inactive or relatively inactive by a local test but on systemic admn. is metabolized to an active substance.