Danazol

Danazol showed weak androgenic effects.

Danazol is a derivative of testosterone and ethisterone. An androgen is any natural or synthetic agent stimulating or controling the development and maintenance of male characteristics by binding to androgen receptors. This includes the activity of the primary male sex organs and development of male secondary sex characteristics.

In vitro: Previous study found that danazol as low as 1 micrometer could suppress LH-stimulated testosterone and androstenedione production in cultured Leydig cells. The addition of danazol to a preparation of testicular microsomes elicited a type I cytochrome P-450 binding spectrum. Danazol could inhibit progesterone and 17alpha-hydroxy-progesterone binding to microsomal P-450 [1].

In vivo: The purpose of a previous study was to examine the role of androgen and estrogen receptors in danazol suppression of luteinizing hormone (LH) in the rat. The estrogen receptor antagonist, LY 156758, partially antagonized the suppressed levels of LH after administration of danazol to ovariectomized rats. In contrast, the androgen receptor antagonist, flutamide, had no effect on suppressed LH levels after danazol treatment, but did partially reverse the inhibition of LH 24 hr after danazol administration to ovariectomized rats [2].

Clinical trial: Danazol was administered to patients with advanced prostate cancer for periods ranging from 3 days to 18 weeks. There were no objective remissions, but three patients had objectively stable disease with complete pain control for periods ranging 15-18 weeks. Seven patients experienced tumor flare reactions, one requiring withdrawal of treatment and one resulting in rapid clinical deterioration and death. Four other patients died within 3 weeks [3].

References:
[1] Barbieri RL, Canick JA, Ryan KJ.  Danazol inhibits steroidogenesis in the rat testis in vitro. Endocrinology. 1977 Dec;101(6):1676-82.
[2] Snyder BW, Beecham GD, Winneker RC.  Danazol suppression of luteinizing hormone in the rat: evidence for mediation by both androgen and estrogen receptors. Proc Soc Exp Biol Med. 1990 May;194(1):54-7.
[3] Cole RM, Raghavan D, Caterson I, Teriana N, Pearson B, Boulas J, Rosen M. Danazol treatment of advanced prostate cancer: clinical and hormonal effects. Prostate. 1986;9(1):15-20.