After baseline information and laboratory tests are obtained, subjects will be randomized to receive either oral paricalcitol at 2 mcg daily for 2 weeks or placebo. After a washout period of 4 weeks, those subjects who received paricalcitol will receive placebo for 2 weeks and those who received placebo will receive paricalcitol for 2 weeks. A simple blood draw will be obtained from the patient on days 0, 1, and 14 of each treatment arm, and they will also be assessed for side effects at the end of each treatment.