Male hormonal contraception : acceptability and investigation of an androgen/progestogen combination, with further investigation of MENT as a novel androgen
Profound suppression of spermatogenesis in normal men can be achieved by testosterone administered alone or in combination with a progestogen. Current regimes result in incomplete suppression to azoospermia and have adverse metabolic side effects. We carried out a dose-finding study using an oral progestogen, desogestrel, in combination with testosterone and demonstrated marked dose dependent gonadotrophin and sperm suppression with no significant change in lipids or behaviour during treatment. These advantageous outcome measures may reflect the avoidance of supraphysiological testosterone concentrations and/or androgenic progestogens. The development of a long acting androgen has been problematic and is likely to be factor in the delay in provision of male hormonal contraception. We have shown that 7α-methyl-19-nortestosterone acetate (MENT Ac) implants inserted into the upper arm of healthy men produced a dose dependent decrease in testosterone and gonadotrophins. It is not known if this suppressive effect of MENT is sufficient to produce azoospermia. The particular advantage of this synthetic androgen is its relative lack of prostatic stimulation. The ability of MENT Ac implants to support androgen-dependent behaviour has not previously been investigated. We showed that MENT has similar effects to testosterone enanthate on sexual interest and activity, spontaneous erection and mood states in hypogonadal men. The appropriate dose of MENT remains to be determined but these resutls support its development as a contraceptive or as a replacement androgen.