Some Effects of Ring-A Structure on the Interaction of 3-Oxo-Steroids of the Androstane Series with Cortisone Reductase.

17β-Hydroxy-5α-androstan-3-ones and related androstene compounds with structural modifications only in ring A were studied as substrates and inhibitors for the reduction of the 3-oxo group by cortisone reductase. Various structural modifications were consistent with substrate function, and several poor substrates and non-substrates served as inhibitors. It is suggested that the steroids fit loosely into a binding region which is probably hydrophobic around the A-ring. [ABSTRACT FROM AUTHOR]