Continuing the search for a hormonal male contraceptive

Abstract

This chapter discusses the mechanisms of action of hormonal male contraception, which suppresses the hypothalamic-pituitary-testis axis. When the intratesticular concentration of testosterone is subsequently suppressed to adequately low concentrations, spermatogenesis is arrested. Androgens are a necessary hormonal male contraceptive component because they not only suppress the hypothalamic-pituitary-testis axis, but also provide the male hormone necessary to maintain peripheral androgen functions. Past studies using testosterone alone and testosterone combined with progestins demonstrated contraceptive efficacy in the female partner at rates similar to combined hormonal female methods. Newer hormonal male contraceptive formulations and the alternative routes of administration are discussed, along with potential barriers, challenges, and opportunities for hormonal male contraceptive development. Novel methods that are safe, effective, reversible, user-friendly, and coitus-independent are intrinsic to equitably meet the various needs and limitations of an increasingly diverse population.

Keywords: Acceptability; Androgens; Male contraception emerging market; Progestins; Spermatogenesis suppression.

Fig. 1.

This figure shows the hypothalamic-pituitary-testis axis. Spermatogenesis is dependent on the high testosterone concentration within the testis and FSH acting on the Sertoli cells to allow the completion of qualitatively and quantitatively normal spermatogenesis. Exogenous androgens and/or progestins or Gonadotropin-Releasing Hormone (GnRH) antagonists suppress the production of LH and FSH leading to low intratesticular testosterone and low Sertoli function resulting in the suppression of spermatogenesis. Androgen action in the men is sustained by the exogenously administered testosterone or another androgen. This is the basis of hormonal male contraception.