None of the studies used any form of post cycle recovery, but fertility returned to normal post cycle despite this
Comparison between testosterone enanthate-induced azoospermia and oligozoospermia in a male contraceptive study. I: Plasma luteinizing hormone, follicle stimulating hormone, testosterone, estradiol, and inhibin concentrations.
Wallace EM, Gow SM, Wu FC.
Department of Clinical Biochemistry, Royal Infirmary Edinburgh, Scotland.
Sex-steroid based male contraceptive regimes induce azoospermia in only 40-70% of Caucasian men. The reason(s) why the remainder maintains a low level of spermatogenesis (oligozoospermia) despite gonadotrophin suppression is unclear. In order to improve our understanding of this phenomenon, we examined the changes in sperm density and plasma LH, FSH, testosterone (T), oestradiol (E2), and inhibin (IN) in 28 normal men who received 200 mg testosterone enanthate (TE) im weekly during a male contraceptive efficacy trial. Gonadotrophins were measured by an ultrasensitive time-resolved immunofluorometric assay (DELFIA) with a sensitivity of 0.04 U/L, to determine the adequacy of suppression. Seventeen of the 28 men achieved azoospermia; the other 11 remained oligozoospermic (sperm density 3.3-4.7 x 10(6)/mL) after 6 months of TE exposure. Azoospermic subjects displayed a more rapid decline in sperm density, a significant difference being apparent by 5 weeks after starting TE. During TE treatment, both LH and FSH were consistently suppressed to below the limits of detection, whereas there was a 2.5-fold rise in T and E2 with a similar decrease in IN. There were no consistent differences in any of these hormone concentrations between the azoospermic and oligozoospermic groups. Recovery of sperm density to baseline levels or above 20 x 10(6)/mL was significantly slower in the azoospermic group. During the recovery phase, the azoospermic men exhibited significantly higher LH and FSH levels compared to baseline and to the oligozoospermic subjects even though no differences in circulating T, E2, or IN were observed. We conclude that incomplete gonadotrophin suppression or differences in sex steroid or inhibin levels are unlikely to be responsible for the maintenance of minor degrees of spermatogenesis in some men during TE administration. The rebound rise in gonadotrophins in azoospermic but not oligozoospermic responders during recovery may reflect a more profound degree of spermatogenic suppression in the former group.
Contraceptive efficacy of testosterone-induced azoospermia in normal men. World Health Organization Task Force on methods for the regulation of male fertility.
A multicentre study (ten centres) in seven countries was done to assess the contraceptive efficacy of hormonally-induced azoospermia in 271 healthy fertile men. Each subject received 200 mg testosterone enanthate weekly by intramuscular injection. 157 men (cumulative rate at 6 months 65%) became azoospermic in three consecutive semen samples. These men entered a 12-month efficacy phase during which continuing testosterone injections were the only form of contraception. There was 1 pregnancy during 1486 months of the efficacy phase (0.8 conceptions [95% confidence interval 0.02-4.5] per 100 person-years). Discontinuations from the study were mainly because azoospermia was not achieved within 6 months and because of dislike of the injection schedule. The mean time to become azoospermic was 120 days (SD 40); reappearance of spermatozoa was detected in 11 men and in no case led to discontinuation from the study or to pregnancy. After the testosterone injections had been stopped, the estimated median time from azoospermia to recovery (sperm concentration of at least 20 million/ml) was 3.7 months (3.6-3.9) and to the subject’s mean baseline sperm concentration was 6.7 months (6.2-8.7). Hormonal regimens that induce azoospermia can provide highly effective, sustained, and reversible male contraception with minimum side-effects.
Induction of azoospermia in normal men with combined Nal-Glu gonadotropin-releasing hormone antagonist and testosterone enanthate.
Tom L, Bhasin S, Salameh W, Steiner B, Peterson M, Sokol RZ, Rivier J, Vale W, Swerdloff RS.
Division of Endocrinology Harbor-University of California-Los Angeles Medical Center, Torrance 90509.
The effects of a combined GnRH antagonist and testosterone (T) replacement regimen on gonadotropins and spermatogenesis were examined to assess its potential as a male contraceptive regimen. The potent Nal-Glu GnRH antagonist ([Ac-D2-Nal1,D4-Cl-Phe2,D3-Pal3,Arg5, D4-p-methoxybenzoyl-2-amino butyric acid6,D-Ala10]GnRH) was administered daily (7.5 mg, sc) to eight normal men for 16 weeks. T enanthate was given im starting at week 2 and every 2 weeks thereafter through week 14 of the treatment phase. Serum LH, FSH, T, and estradiol concentrations were measured frequently during the 5-week control period, the 16-week treatment phase, and the 14-week recovery phase. Semen analyses were performed every week during the control phase and every 2 weeks during the treatment and recovery phases. Seven of eight subjects became azoospermic by 6-10 weeks of treatment; the eighth subject, who failed to achieve azoospermia, suppressed his sperm count to 7 million/mL by week 14 (from a mean baseline of 42 million/mL) before treatment was prematurely terminated because of localized swelling at each of his injection sites. Sperm counts returned to baseline 10-14 weeks after the end of Nal-Glu administration. Seven of the eight subjects showed suppression of LH to the limit of assay detection (less than 0.2 U/L), whereas the eighth subject showed incomplete suppression. Serum bioactive and immunoreactive LH concentrations showed concordant responses. Mean serum FSH concentrations were also markedly suppressed. Serum T and estradiol concentrations declined dramatically during the first 2 weeks of Nal-Glu GnRH treatment, but returned to the normal physiological range after T enanthate replacement was initiated. Libido and sexual potency were maintained. No systemic side-effects, other than erythema and induration at injection sites, were observed. These data demonstrate that combined GnRH antagonist plus T treatment can predictably and reversibly induce azoospermia in most men and has potential as a male contraceptive regimen.
The individuals here used a much greater dose then just 40 mg/day.
Mr jones and me..... Gonna be big stars