Manipulation of the Intratesticular Hormonal Milieu With Exogenous Testosterone (Short Title (HOP-3)

Three study drugs will be used in this study: Testim (testosterone gel), Human Chorionic Gonadotropin (hCG) and acyline. Testosterone is a naturally occurring hormone in men. When given to normal men, testosterone gel will temporarily lower the amount of testosterone in the testes and lower sperm counts. hCG is a female hormone produced during pregnancy that is similar to and has the same actions as a male hormone, luteinizing hormone (LH). Like LH, hCG stimulates the testis to produce testosterone and sperm, and is used in the treatment of men who are deficient in LH. When hCG is given together with testosterone to normal men, the amount of testosterone in the testes will change, dependent on the amount of hCG received. Some participants will receive placebo hCG injections (no active medication).

Acyline suppresses LH (luteinizing hormone) and FSH (follicle stimulating hormone), which are hormones made by the pituitary gland in the brain, thus blocking the signal from the brain that causes the testes to make testosterone. Therefore, acyline blocks testosterone production. Men may experience some side effects from the low levels of testosterone caused by acyline.

Acyline is an experimental drug. Testosterone gel and hCG are approved for use in men with low testosterone levels. The U.S. Food and Drug Administration (FDA) allows testosterone gel, hCG and acyline to be given in combination for research to a small number of volunteers. Over 125 men have received acyline. Both Acyline and hCG will be given by injection. Acyline injections are formulated by subjects weight and may be given in multiple injections.

Participation will last approximately 2 months. The study involves a minimum of 9 visits in Seattle, WA. Clinic visits at Screening, Day 1 and Day 10 will take about 1-1.5 hours each. On Day 1 & 10 a fine needle aspiration of one testis will be performed. The Day 7, Day 17, and Day 40 visits will take approximately 30 minutes. The other visits will take about 15 minutes each time. Over the course of the study, which includes 5 separate blood draws, approximately 12 ounces (one and a half cups) of blood will be drawn. Some of the study drugs will be given by injection. One drug is a topical gel.

This is NOT a trial of a male contraceptive, and the study medications will not prevent pregnancy. Subjects must use an acceptable form of birth control.