Male hormonal contraception requires the administration of exogenous testosterone to suppress the pituitarygonadotropins FSH and LH. Current methods of testosterone delivery include intramuscular injections,implants, or a daily transdermal patch or gel, since oral administration of testosterone (in contrast to othersteroids) was thought to be impractical. Nevertheless, we have recently shown that oral administration oftestosterone (in the form of testosterone enanthate) results in normal levels of serum testosterone when coadministeredwith the 5-alpha-reductase inhibitor dutasteride. We believe that oral testosterone enanthateplus dutasteride might be a useful part of a male hormonal contraceptive regimen. However, no informationexists about the ability of oral testosterone to suppress gonadotropin release and spermatogenesis in normalmen the subject of this proposal. Specifically, our aims in this proposal are:1) To determine the optimal dose of oral testosterone enanthate plus dutasteride to suppressgonadotropin secretion in men over a four week period.2) To determine the best dose combination of oral testosterone/dutasteride and the oral progestogenmedroxyprogesterone acetate to suppress gonadotropin secretion in men over an eight week period.3) To determine the degree of spermatogenic suppression induced by combinations of oral testosterone,dutasteride and medroxyprogesterone acetate over a six month period.The experiments proposed in this submission will explore the ability of oral testosterone plus dutasteridecombined with medroxyprogesterone to function as a hormonal contraceptive in man. Testosteroneenanthate, dutasteride and medroxyprogesterone acetate are all commercially available and are safe for usein humans. These innovative studies will provide insight into the utility of oral testosterone and progestogensfor male contraception, the physiology of gonadotropin suppression and the impact of oral testosteroneadministration on the maintainence of mood and sexual function in the setting of a male hormonalcontraceptive regimen. In addition, this work might assist in the development of novel androgen therapiesfor men with testosterone deficiency. These studies will greatly inform efforts to create a usable, attractivereversible oral hormonal contraceptive for men, and help bring the dream of a 'male pill' to fruition.PERFORMANCE SITE(S) (organization, city, state)University of Washington, Seattle, WA, USAPHS 398 (Rev. 04/06) Page 114 Form Page 2
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