Nonhormonal mediation of male reproductive tract damage: data from contraceptive drug research.

Chemicals can interfere with hormonal control of the male reproductive tract and/or directly alter male reproductive tract function. A review is presented of those chemicals developed and tested as male contraceptive agents which have a direct effect on the male reproductive tract with minimal disturbance of the hormonal milieu. Such chemicals can have one or more sites of action: 1) the testis, disturbing spermatogenesis; 2) the epididymis, altering sperm maturation; 3) the vas deferens, affecting sperm transport; and 4) the accessory sex glands, entering the ejaculate and changing the functional activity of the spermatozoa. Examples of each mode of action are presented.