Serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin in chronic renal failure.

Serum 1,25-dihydroxyvitamin D (1,25(OH)2D) is normal in some patients with chronic renal failure. We studied the question, whether factors known to regulate the serum 1,25(OH)2D concentration such as parathyroid hormone, calcium, phosphate and especially the serum 25 hydroxy vitamin D (25 OH D) concentration are related to circulating levels of serum 1,25(OH)2D in such patients. We found no correlation between these serum parameters and 1,25(OH)2D. Our data indicate that other factors are of more importance for the regulation of serum 1,25(OH)2D in this situation.