Direct and indirect effects of docosanol (IK.2), the active principle in Tadenan, on the rat prostate

To better understand the mode of action of Tadenan, a drug used in the treatment of benign prostatic hyperplasia, the effect of its active principle docosanol, IK.2, was investigated in rats. IK.2 had no effects on the weight and histologic appearance of the prostate in intact rats but increased the RNA/DNA quotient in the ventral prostate. The plasma concentrations of luteinizing hormone and testosterone were reduced. In orchiectomized animals IK.2 increased the weight of the prostate and the adrenals. In adrenalectomized, orchiectomized animals IK.2 did not increase prostatic weight but on the contrary caused a further weight reduction. IK.2 had a thymolytic effect in intact rats but not in adrenalectomized rats in which the thymus weight was increased. The results indicate that IK.2 increases adrenal steroid secretion. The supposedly higher concentration of adrenal androgens causes a stimulation of the prostate most easily discernible in orchiectomized animals. The further weight reduction of the ventral prostate in orchiectomized, adrenalectomized animals, and the increased thymus weight in adrenalectomized animals after IK.2 administration may suggest that IK.2 has effects other than the stimulatory effect on the adrenals.