Oduwole OO, Huhtaniemi IT. Feasibility of Male Hormonal Contraception: Lessons from Clinical Trials and Animal Experiments. Curr Mol Pharmacol. http://benthamscience.com/journal/abstracts.php?journalID=cmp&articleID=128013
The general interest in the availability of male contraceptives is on the increase across different cultures and ethnic backgrounds, due in part to the fact that men are now willing more than ever, to share the responsibility of family planning.
Despite the expression of interest and tremendous advances in research however, a modern male hormonal contraceptive method has remained an elusive goal.
Testosterone (T) alone, or in combination with a progestin currently provides the most promising lead to male hormonal contraception. The principle relies on enhanced negative feedback of exogenous T to suppress gonadotropins, thereby blocking the endocrine stimulus for the process of spermatogenesis.
A serious drawback is the inconsistent suppression among men of different ethnic backgrounds. This has increased the quest for development to include other nonhormonal methods.
In reality many obstacles still have to be overcome before an acceptable method is available. In this review, we highlight recent developments in male hormonal contraceptives methods.
Based on our recent findings from animal experiment, we shed light on why the method is not achieving the intended results, and suggest possible ways forward.
Fig. (1). The hypothalamic-pituitary-gonadal axis, with feedback loops of endogenous sex steroids (left) and site of inhibitory actions of contraceptive hormones (right). Hyp = hypothalamus; Pit = pituitary gland.
Fig. (2). Depiction of the 100-fold higher level of T in the human testis in comparison with the serum level of the hormone. The comparison of the antigonadotropic steroid without androgenic effect and with add-back T effect are also as indicated. For contraceptive efficacy, the testicular T levels must decrease below the threshold required to maintain spermatogenesis. If the antigonadotrpic treatment is devoid of T, then an add-back dose will be necessary to provide the required levels for the maintenance of the extragonadal effects. Legend: T = Testis; S = Serum.
The general interest in the availability of male contraceptives is on the increase across different cultures and ethnic backgrounds, due in part to the fact that men are now willing more than ever, to share the responsibility of family planning.
Despite the expression of interest and tremendous advances in research however, a modern male hormonal contraceptive method has remained an elusive goal.
Testosterone (T) alone, or in combination with a progestin currently provides the most promising lead to male hormonal contraception. The principle relies on enhanced negative feedback of exogenous T to suppress gonadotropins, thereby blocking the endocrine stimulus for the process of spermatogenesis.
A serious drawback is the inconsistent suppression among men of different ethnic backgrounds. This has increased the quest for development to include other nonhormonal methods.
In reality many obstacles still have to be overcome before an acceptable method is available. In this review, we highlight recent developments in male hormonal contraceptives methods.
Based on our recent findings from animal experiment, we shed light on why the method is not achieving the intended results, and suggest possible ways forward.
Fig. (1). The hypothalamic-pituitary-gonadal axis, with feedback loops of endogenous sex steroids (left) and site of inhibitory actions of contraceptive hormones (right). Hyp = hypothalamus; Pit = pituitary gland.
Fig. (2). Depiction of the 100-fold higher level of T in the human testis in comparison with the serum level of the hormone. The comparison of the antigonadotropic steroid without androgenic effect and with add-back T effect are also as indicated. For contraceptive efficacy, the testicular T levels must decrease below the threshold required to maintain spermatogenesis. If the antigonadotrpic treatment is devoid of T, then an add-back dose will be necessary to provide the required levels for the maintenance of the extragonadal effects. Legend: T = Testis; S = Serum.
