Effect of long-term administration of 1,25-dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 on the calcium content of the aorta, heart and kidney of normal and uremic rats.

Studies in uremic rats were performed to see whether or not the long-term administration of therapeutical doses of 1,25-Dihydroxyvitamin D3 or 1 alpha-hydroxyvitamin D3 would induce histological changes in the aorta or increase the calcium content of the aorta or the heart. In contrast to observations of others, no effect of both vitamin D sterols could be observed on both investigated tissues. However, the remnant kidneys of the rats treated with both vitamin D compounds showed a significantly increased calcium content. According to these results one cannot exclude that the chronic application of active vitamin D metabolites has induced a calcium deposition in the remnant kidney. This finding deserves special attention, although we found, on the other hand, no evidence that an underlying arterial disease is aggravated by this therapy.