Cellular regulation of the metabolism of androgens in rat oral mucosa. III. Activation of delta 4-3-ketosteroid-5alpha-A ring reductase enzyme system by 5,5-diphenylhydantoin.

Systemic pretreatment of rats with diphenylhydantoin (DPH) or its addition into an in vitro assay increases 5alpha-reduction of testosterone by the oral mucosa. Enzyme kinetic studies showed that DPH binds to the enzyme and probably activates it by an allosteric mechanism.