Comparison of 1,25(OH)2D3 and 24,25(OH)2D3 in the long-term treatment of renal osteodystrophy.

24,25(OH)2D3 has been compared with 1,25(OH)2D3 in the treatment of renal osteodystrophy. Treatment with 24, 25(OH)2D3 2 micrograms/day for 5-7 months was accompanied by deterioration in clinical, biochemical, radiological and histological features of osteodystrophy with no increase in Ca absorption. In contrast, treatment with 1,25(OH)2D3 0.25--1 microgram/day for 6-15 months resulted in rapid improvement in clinical, biochemical, radiological and histological features and a return of Ca absorption to normal. It is concluded that in the dose used 24,25(OH)2D3 alone is not an effective treatment for renal osteodystrophy.