title: Induction of azoospermia in normal men with combined Nal-Glu gonadotropin-releasing hormone antagonist and testosterone enanthate.
abstract: 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.
authors.affiliation: Division of Endocrinology Harbor-University of California-Los Angeles Medical Center, Torrance 90509.
authors.forename: L
authors.initials: L
authors.lastname: Tom
authors.forename: S
authors.initials: S
authors.lastname: Bhasin
authors.forename: W
authors.initials: W
authors.lastname: Salameh
authors.forename: B
authors.initials: B
authors.lastname: Steiner
authors.forename: M
authors.initials: M
authors.lastname: Peterson
authors.forename: R Z
authors.initials: RZ
authors.lastname: Sokol
authors.forename: J
authors.initials: J
authors.lastname: Rivier
authors.forename: W
authors.initials: W
authors.lastname: Vale
authors.forename: R S
authors.initials: RS
authors.lastname: Swerdloff
mesh_terms: D000328:Adult; D003272:Contraceptive Agents, Male / Q000494:pharmacology*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006728:Hormones / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009845:Oligospermia / Q000139:chemically induced*; D012016:Reference Values; D012725:Sexual Behavior / Q000187:drug effects; D013076:Sperm Count / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology; D013739:Testosterone / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D003272:Contraceptive Agents, Male; D006728:Hormones; C057805:LHRH, N-Ac-2-Nal(1)-4-Cl-Phe(2)-3-Pal(3)-Arg(5)-Glu(6)-AlaNH2(10)-; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; C004648:testosterone enanthate