7α-methyl-19-nortestosterone (MENTR): the population council's contribution to research on male contraception and treatment of hypogonadism.

Testosterone is an essential part of all regimens for hormonal male contraception tested to date. Initial efficacy trials revealed that the half-life of the testosterone preparations available at that time was too short to be used for male contraception. The ensuing search for long-acting preparations yielded testosterone buciclate and undecanoate as well as 7α-methyl-19-nortestosterone (MENT). Following description of the principle of male hormonal contraception and the efficacy trials performed to date, the systematic development of MENT for substitution of male hypogonadism and use in male contraception by the Population Council is reviewed here.