Bone age advancement, however, was not slowed by spironolactone and gynecomastia had begun to occur in a number of patients. Both of these processes may be the result of persisting elevated estradiol levels. To attempt to reduce elevated estrogen levels in these patients to normal prepubertal levels, we plan to use testolactone (Teslac) to inhibit aromatase, the last step of estrogen biosynthesis. Testolactone has previously been used for a similar purpose in girls with gonadotropin-independent precocious puberty (McCune-Albright Syndrome) under protocol 82-CH-0165, "Testolactone treatment of girls with LHRH analog-resistant precocious puberty due to autonomous non-neoplastic ovarian estrogen secretion."