The male sex steroid hormones, or androgens, act on target organs via a general mechanism common to all steroid hormones. According to this mechanism, 1 , 2 the steroid hormone, upon entering its target cell, binds to a specific high affinity cytosol receptor. The steroid receptor complex thus formed undergoes a temperature-dependent activation process or transformation of the receptor and translocates to the nucleus. In the nucleus, the steroid-receptor complex binds readily to chromatin with ensuing unspecified events leading to an altered pattern of gene expression. Simply stated, the action of steroid hormones is primarily regulation of steroid-specific gene activities.