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dc.contributor.authorMatsumoto, Alvin M.en_US
dc.contributor.authorBremner, William J.en_US
dc.contributor.authorAmory, John K.en_US
dc.contributor.authorAnawalt, Bradley D.en_US
dc.date.accessioned2008-10-17T20:41:44Z
dc.date.available2008-10-17T20:41:44Z
dc.date.issued2001-11en_US
dc.identifier.citationJ Androl. 2001 Nov-Dec;22(6):1053-60en_US
dc.identifier.urihttp://hdl.handle.net/1773/4372
dc.description.abstractWeekly intramuscular administration of testosterone esters such as testosterone enanthate (TE) suppresses gonadotropins and spermatogenesis and has been studied as a male contraceptive. For unknown reasons, however, some men fail to achieve azoospermia with such regimens. We hypothesized that either 1) daily circulating serum fluoroimmunoreactive gonadotropins were higher or testosterone levels were lower during the weekly injection interval, or 2) monthly circulating bioactive gonadotropin levels were higher in nonazoospermic men. We therefore analyzed daily testosterone and fluoroimmunoreactive gonadotropin levels as well as pooled monthly bioactive and fluoroimmunoreactive gonadotropin levels in normal men receiving chronic TE injections and correlated these levels with sperm production. After a 3-month control period, 51 normal men were randomly assigned to receive intramuscular TE at 25 mg (n = 10), 50 mg (n = 9), 100 mg (n = 10), 300 mg (n = 10), or placebo (n = 12) weekly for 6 months. After 5 months of testosterone administration, morning testosterone and fluoroimmunoreactive follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured daily for a 1-week period between TE injections. In addition, fluoroimmunoreactive and bioactive FSH and LH levels were measured in pooled monthly blood samples drawn just before the next TE injection. In the 100-mg and 300-mg TE groups, mean monthly fluoroimmunoreactive FSH and LH levels were suppressed by 86%-97%, bioactive FSH and LH levels by 62%-80%, and roughly half the subjects became azoospermic. In the 1-week period of month 6, daily testosterone levels between TE injections were within the normal range in men receiving placebo, or 25 or 50 mg of weekly TE, but were significantly elevated in men receiving 100 or 300 mg of weekly TE. At no point during treatment, however, were there significant differences in daily testosterone or fluoroimmunoreactive gonadotropin levels, or monthly bioactive gonadotropin levels between men achieving azoospermia and those with persistent spermatogenesis. This study, therefore, demonstrates that neither monthly nor daily differences in serum testosterone, or fluoroimmunoreactive or bioactive gonadotropins explain why some men fail to completely suppress their sperm counts to zero with weekly TE administration. Innate differences in the testicle's ability to maintain spermatogenesis in a low-gonadotropin environment may explain persistent spermatogenesis in some men treated with androgen-based contraceptive regimens.en_US
dc.language.isoen_USen_US
dc.publisherAmerican Society of Andrologyen_US
dc.subjectcontraceptionen_US
dc.subjectgonadotropinsen_US
dc.subjectazoospermiaen_US
dc.subject.meshResearch Support, U.S. Gov't, Non-P.H.S.en_US
dc.subject.meshReference Valuesen_US
dc.subject.meshSemen, chemistryen_US
dc.subject.meshResearch Support, U.S. Gov't, P.H.S.en_US
dc.subject.meshComparative Studyen_US
dc.subject.meshAdulten_US
dc.subject.meshInjections, Intramuscularen_US
dc.subject.meshContraceptive Agents, Male, administration & dosage, pharmacologyen_US
dc.subject.meshTestosterone, administration & dosage, analogs & derivatives, blood, pharmacologyen_US
dc.subject.meshMaleen_US
dc.subject.meshOligospermia, blooden_US
dc.subject.meshLuteinizing Hormone, blooden_US
dc.subject.meshFollicle Stimulating Hormone, blooden_US
dc.subject.meshHumansen_US
dc.titleDaily testosterone and gonadotropin levels are similar in azoospermic and nonazoospermic normal men administered weekly testosterone: implications for male contraceptive developmenten_US
dc.typeArticleen_US


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