title: A non-human primate study (baboon; Papio hamadryas) to determine if a long-acting progestogen, levonorgestrel butanoate, combined with a long-acting androgen, testosterone buciclate, can suppress spermatogenesis: I. Dose-finding study.
abstract: This study in adult male baboons was conducted to establish the dose of a long-acting progestogen, levonorgestrel butanoate, and that of a long-acting androgen, testosterone buciclate, which, when combined, would achieve optimal and prolonged suppression of spermatogenesis. Two intramuscular injections of levonorgestrel butanoate at 3-month intervals and in the dose range 1-8 mg/kg reduced sperm production and plasma concentrations of testosterone, LH and FSH for periods of up to 6 months. The suppression of sperm production was greatest and most prolonged in the 4 mg/kg group. Two intramuscular injections of testosterone buciclate at 3-month intervals, and at doses of 4 and 8 mg/kg, induced variable changes in circulating levels of testosterone, elevated by the higher dose, and caused sperm suppression, in some animals to azoospermia. It was concluded that 8 mg/kg testosterone buciclate would provide adequate androgen replacement when combined with 4 mg/kg levonorgestrel butanoate as a putative male contraceptive regimen.
authors.affiliation: WHO Collaborating Centre, Institute of Experimental Pathology and Therapy, Sukhumi, Republic of Georgia.
authors.forename: N P
authors.initials: NP
authors.lastname: Goncharov
authors.forename: G V
authors.initials: GV
authors.lastname: Katzia
authors.forename: V U
authors.initials: VU
authors.lastname: Butnev
authors.forename: E G
authors.initials: EG
authors.lastname: Richkor
authors.forename: T
authors.initials: T
authors.lastname: Matikainen
authors.forename: G M
authors.initials: GM
authors.lastname: Waites
mesh_terms: D000305:Adrenal Cortex Hormones / Q000378:metabolism; D000818:Animals; D004305:Dose-Response Relationship, Drug; D006062:Gonadotropins / Q000037:antagonists & inhibitors; D016912:Levonorgestrel / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009644:Norgestrel / Q000031:analogs & derivatives* / Q000494:pharmacology; D010215:Papio; D013076:Sperm Count / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects*; D013739:Testosterone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000305:Adrenal Cortex Hormones; D006062:Gonadotropins; C050320:testosterone 4-n-butylcyclohexylcarboxylic acid; D009644:Norgestrel; D013739:Testosterone; D016912:Levonorgestrel; C095485:levonorgestrel butanoate