Study of Spermatogenesis Suppression With DMAU Alone or With LNG Versus Placebo Alone in Normal Men

This 12 week repeated dose study will be conducted at two centers: the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center and the University of Washington. The sites propose to enroll approximately 100 men with a goal of enrolling 20 healthy male subjects in each of the 4 active groups and 20 in the placebo group for 12 weeks of treatment. The goal is to complete at least 17 efficacy evaluable subjects in each group. The DMAU for this study will be castor oil formulation administered after a 25 to 30 g fat meal. The oral dose of LNG will be 30 mcg per day. The study volunteers will be randomized to one of five treatment groups: Group 1: Lower DMAU dose (100 mg per day) + LNG (30 mcg per day) (n=20) Group 2: Middle DMAU dose (200mg per day) + LNG (30 mcg per day) (n=20) Group 3: Middle DMAU dose (200 mg per day) + placebo LNG (n=20) Group 4: Higher DMAU dose (400 mg per day) + placebo LNG (n=20) Group 5: Placebo DMAU capsules and placebo LNG capsules (n=20) Each treatment group will receive the identical number of capsules in blinded fashion so that each subject will receive an identical number of capsules in order to maintain the blind.