Circulating levels of vitamin D metabolites after renal transplantation

We investigated the change in the serum levels of vitamin D metabolites after renal transplantation in 5 uremic children. The serum 1,25-(OH)2D level showed a transient increase on the 1st or 2nd day after transplantation in all the patients. In 3 cases, it decreased after the initial peak and increased gradually to the normal level again within 2-4 weeks although, in the other 2 cases, it remained within the normal range after a slight decline. Serum 25-OHD and 24,25-(OH)2D level remained low for 4-8 weeks. Hypophosphatemia and/or hyperparathyroidism, which still remained after transplantation, may possibly stimulate 1 alpha-hydroxylase in the transplanted kidney.