Antifertility actions of alpha-chlorohydrin in the male.

Non-steroidal chemicals that affect male fertility have been known for over 25 years but only one compound, alpha-chlorohydrin, possesses most of the attributes of an ideal male contraceptive. In the male rat, for example, continuous daily oral administration of low doses produces an almost immediate and continuous antifertility response that ceases when treatment is withdrawn. Such a dose regime does not interfere with libido, is apparently not toxic and the action is specific towards mature sperm. Furthermore, the action of the compound is species-specific: it is effective in the rat, ram, boar, guinea pig, hamster, rhesus monkey and upon ejaculated human sperm but it is ineffective in the mouse and the rabbit. High doses of alpha-chlorohydrin can be neurotoxic, nephrotoxic and, in rats, lead to prolonged or permanent infertility. However, the antifertility response and the toxicity of racemic alpha-chlorohydrin may be due, respectively, to the separate enantiomers. No other antifertility chemical has been investigated to such an extent as alpha-chlorohydrin; this article reviews the progress that has been achieved with alpha-chlorohydrin during the past six years.