Thus far, when tested as male contraceptives, GnRH agonists in combination with androgens were not very effective in producing azoospermia. Since in previous studies androgens were always given simultaneously with the GnRH agonist or later, we tested whether GnRH agonist administration after an initial androgen suppression phase might yield better results. After a control period, 3 groups of young healthy men (n = 8/group) received an initial loading dose of 400 mg 19-nortestosterone hexyloxyphenylpropionate (19NT-HPP), followed by 200 mg of the ester every 3 weeks for 24 weeks. One week after the first 19NT-HPP injection, 2 groups were given a single sc implant injection of 3.3 or 6.6 mg of the GnRH agonist buserelin, respectively, whereas a placebo implant was given to the third group. In the group receiving only 19NT-HPP, serum LH and FSH were markedly suppressed and remained low during the treatment phase. In the 16 volunteers receiving the buserelin implant LH and FSH were also suppressed on day 7, followed by a marked increase in the gonadotropins up to 2 weeks after buserelin implant injection. While LH was consistently suppressed for the remaining treatment phase, FSH returned to almost normal values in weeks 9-15. In contrast to the group treated with 19NT-HPP alone, in which sperm concentrations were reduced to oligozoospermia after only 3 weeks of treatment, the first suppressive effect in the 19NT-HPP/buserelin-treated groups was not seen before week 9. After 30 weeks, when the maximal suppression of spermatogenesis was seen, 4 of 8 volunteers in the group treated with 19NT-HPP alone were azoospermic, and the remaining 4 volunteers were oligozoospermic. In the groups treated with 19NT-HPP/buserelin, no more than 4 of 16 volunteers were azoospermic, and no more than 8 of 16 volunteers were oligozoospermic at any time point. It is concluded that GnRH agonist depot preparations have a blunting effect on the suppression of pituitary and testicular function caused by androgens in men participating in contraceptive trials.
PIP: Administration of a depot gonadotropin-releasing hormone agonist (buserelin, Hoechst, Frankfurt am Main, Germany, GnRH) 7 days after full suppression of spermatogenesis with depot androgen, nortestosterone enanthate, reduced the degree of azoospermia compared to treatment with androgen alone. 3 groups of 8 men were given 400 mg 19-nortestosterone hexyloxyphenylpropionate (Anadur, Pharmacia Arzneimittel, Ratigen, Germany, 19NT-HPP) then 200 mg every 3 weeks for 24 weeks. The 3 groups then received a single sc implant of 3.3 or 6.6 mg GnRH or a placebo. In the 19NT-HPP-placebo group, LH and FSH both were fully suppressed throughout treatment, and 1 to 4 men were azoospermic from weeks 6-30. In contrast, in the men given GnRH agonist, LH and FSH were suppressed at first, spiked initially, then FSH rose to a maximum at 12 weeks, declined, and again rose to normal levels after week 27. Testosterone mirrored LH in remaining suppressed throughout. The appearance of azoospermia was noted in 6 weeks in Group 1, in 12 weeks in Group 2, and in 24 weeks in Group 3. Azoospermia lasted longest in Group 1 (median length 21 weeks), shortest in Group 3 (median 6 weeks). Testicular volume, sperm concentration and motility followed similar trends. The only change in clinical findings was increased hemoglobin and hematocrit in all groups. Subjects reported no change in physical symptoms or frequency of coitus, but a few men in each group noted decreased in libido in Week 9. These results corroborate previous studies which showed less inhibition of spermatogenesis in men given GnRH in addition to androgens. Apparently androgens with GnRH antagonists are more effective in male effective in male contraception than GnRH agonists.