Cui, Yu-GuiWang, Xing-HaiBremner, William J.Zhang, Gui-YuanGu, Yi-Qun2008-10-172008-10-171999-10J Clin Endocrinol Metab. 1999 Oct;84(10):3642-7http://hdl.handle.net/1773/4404This is a pilot dose-finding study of spermatogenic suppression using testosterone undecanoate (TU) injections alone in normal Chinese men. Thirty-two healthy men were recruited. Volunteers underwent pretreatment evaluation, then a treatment period in which group I (n = 13) received 500 mg TU, group II (n = 12) received 1000 mg TU, and group III (n = 7) received placebo, respectively, at monthly intervals during the treatment period (or until azoospermia was achieved). Thereafter, they underwent a recovery period until all parameters returned to pretreatment levels. Eleven of 12 volunteers in the 500-mg TU group, and all volunteers in the 1000-mg TU group became azoospermic. Faster suppression of spermatogenesis was achieved in the 1000-mg TU group. Serum testosterone increased significantly in the higher dose group at weeks 8 and 12, but remained within the normal range. Mean serum LH and FSH were profoundly suppressed by both doses to undetectable levels at week 16. TU injections did not cause a significant change in high density lipoprotein cholesterol levels. No serious side-effects were found. We conclude that both dosages of TU can effectively, safely, and reversibly suppress spermatogenesis in normal Chinese men.en-USmale contraceptionandrologygonadotropins5-alpha reductase inhibitorsspermatogenesistestosteronecolchicineklinefelter's syndromereifenstein's syndromeContraceptive Agents, Male, administration & dosage, adverse effects, pharmacologyResearch Support, Non-U.S. Gov'tSperm Count, drug effectsBody Weight, drug effectsDouble-Blind MethodHemoglobins, analysisDose-Response Relationship, DrugTestosterone, administration & dosage, adverse effects, analogs & derivatives, pharmacologyMaleHumansInjectionsOrgan Size, drug effectsGonadal Steroid Hormones, bloodAdultAsian Continental Ancestry GroupLipids, bloodTestis, anatomy & histologyReference ValuesPilot ProjectsMiddle AgedArticle