After Subjects have received the medication for 3 months they will again be admitted to the GCRC, this time for 2 days during which they will continue to take the medication with the same measurements as on the last 2 days of the first admission. The same admission will be repeated after 12 months of treatment. During each of these admissions, you will have 80 mL (about 5 ½ tablespoons) of blood drawn.