Binding of Permixon, a new treatment for prostatic benign hyperplasia, to the cytosolic androgen receptor in the rat prostate.

The benign hyperplasia of the prostate is a manifestation of aging, involving the accumulation, within the gland, of dihydrotestosterone, the probable mediator of the hyperplasia. Binding studies were performed on the cytosolic androgenic receptor of the rat prostate using [3H]methyltrienolone as a ligand. The binding of [3H]methyltrienolone at 5 nM, was inhibited by various drugs, such as methyltrienolone and cyproterone acetate. Permixon, a liposterolic extract of the plant, Serenoa Repens B, inhibits competitively the binding to the cytosolic receptor of the rat prostate. Various vegetable and mineral oils, the plant steroid: beta sitosterol and the antiprostatic drug: Tadenan, were all found to be inactive. The antiprostatic activity of Permixon shown in animal studies and controlled clinical trials, may thus result from a direct action at the cytosolic receptor.