Pharmacokinetic Comparison of Vitamin's D2 and D3 in Stage 5 Chronic Kidney Disease Patients on Chronic Hemodialysis

This is a randomized, single blind, controlled study. Subjects will be randomly assigned to
receive 1) placebo capsules (control group); 2) capsules with ergocalciferol (the vitamin D2
group); or 3) capsules with cholecalciferol (the vitamin D3 group).

Inclusion Criteria:

- 30 men and women, ages 20-65, BMI 18-30, requiring chronic hemodialysis

Exclusion Criteria:

- They will habitually consume less than 16 oz of milk per day and get less than 10
hours of sun exposure per week. We will exclude those with granulomatous conditions,
cirrhotic liver disease, and those taking anticonvulsants, barbiturates, or steroids
in any form or any investigational drugs within 4 weeks. We will exclude those with
pregnancy or planned pregnancy, hypercalcemia (>10.4 mg/dl) previously recorded,
chronic GI disease which would interfere with absorption, any allergy to vitamin D3,
or chronic vitamin D intake >1,000 IU daily. Subjects will continue to take a
calcitriol analogue and phosphorus binder as prescribed by their nephrologist.
Calcitriol analogues are to be documented and remain constant throughout study.