• Changes in RNA expression as a result of ergocalciferol [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
  

The goals of this study are to elucidate the function of extrarenal 1 alpha-hydroxylase activity in the setting of renal failure and to evaluate the role of nutritional vitamin D deficiency as a potential contributor to the morbidity witnessed in patients with end-stage renal disease (ESRD). This study will consist of patients on chronic maintenance hemodialysis three times per week who have been identified to have nutritional vitamin D deficiency. After consent for study enrollment, patients will undergo baseline blood sampling prior to a 4 week washout period of all active vitamin D supplementation. After washout is complete, an additional blood sample will be obtained. These two initial blood samples will be saved for later isolation of peripheral monocytes for measurement of mRNA expression. Additionally, vitamin D levels will be measured from the second sample to establish baseline levels prior to treatment. After this baseline sampling, patients will be started on cholecalciferol therapy 50,000 IU twice weekly. Serum 25-vitamin D levels will be monitored throughout study and dosing adjusted as further described in detail within the protocol section. After 8 weeks of therapy with cholecalciferol, post-treatment blood sample will be taken in order to once again isolate peripheral monocytes and measure gene response activity.