Receptor binding of B-norsteroids.

The binding of B-nor-analogues of glucocorticoids, estrogens and of an androgen to specific cytosol receptors was compared with that of parent compounds of the normal series. In the study of binding of B-norcortisol and related compounds rat liver cytosol was used, while in a case of B-norestrogens rat uterus cytosol and for 17 alpha-methyl-B-nortestosterone rat prostate cytosol was used. The displacement of the appropriate radioligands by B-norsteroids was remarkably lower than that caused by correspondinga steroids with normal B-ring with the exception of 17 alpha-methyl-B-nortestosterone.