3 β-Methoxy-5-androsten-16 β-ol: a cytostatic and fungistatic steroid.

IN our search for a superior ‘androgenic’ steroid for use in human cancer of the breast, we have submitted many such steroids to study in the zebra fish-egg test1. Using this bioassay method for determination of cytostatic activity, intensely cytostatic compounds in the C-19 or ‘androgenic’ steroids are difficult to find. To date, our most active compound is 3β-methoxy-5-androsten-16β-ol2, this steroid having LD50 of 1–2 parts per million. It is very interesting that this compound is the exact analogue of the steroidal œstrogen 3-methoxyœstra-1-3,5(10)-trien-16β-ol3, which had been previously selected by us for use against cancer of the prostate, based on fish-egg cytostasis4. Also of much interest in steroidal cytostasis is the fact that methyl ether formation at C3 of 5-androstene-3β,16β-diol2 so strongly enhances the activity of this diol, which itself is virtually inactive (LD50 > 10 p.p.m.). Methyl ether formation at C3 of l,3,5(10)-œstratrien-3,16β-diol3 had also caused an enhancement (100 per cent) of cytostatic activity in the fish-egg test.