Determination Of 17 Alpha-Hydroxylase-C-17,C-20-Lyase (P450(17 Alpha)) Enzyme Activities And Their Inhibition By Selected Steroidal Picolyl And Picolinylidene Compounds

17 alpha-hydroxylase-C-17,C-20-lyase (P450(17 alpha)) is a key regulator enzyme of the steroid hormone biosynthesis in both the adrenals and the testes. Inhibition of this enzyme can block androgen synthesis in an early step, and may thereby be useful in the treatment of several androgen-dependent diseases. We developed radiosubstrate in vitro incubation methods for the determination of the distinct 17 alpha-hydroxylase and C-17,C-20-lyase activities of the enzyme using rat testicular homogenate as enzyme source. With this method we have studied the inhibiting activity of selected steroidal picolyl and picolinylidene compounds. Tests revealed a substantial inhibitory action of the 17-picolinyliden-androst-4-en-3-one compound.