American journal of kidney diseases : the official journal of the National Kidney Foundation
-
We have previously reported that 19-nor-1,25-(OH)2D2, a new analog of 1,25-(OH)2D3, suppresses parathyroid hormone (PTH) secretion in uremic rats in the absence of hypercalcemia or hyperphosphatemia. In the current study, we examined the effect of 19-nor-1,25-(OH)2D2 on parathyroid gland growth and intestinal vitamin D receptor (VDR) content. After induction of uremia by 5/6 nephrectomy, rats were divided into five experimental groups and received intraperitoneal injections of vehicle, 1,25-(OH)2D3 (2 or 6 ng/rat), or 19-nor-1,25-(OH)2D2 (25 or 100 ng/rat) three times a week for 8 weeks. ⋯ Thus, 19-nor-1,25-(OH)2D2 appears to exert a selective action on the parathyroid glands compared with the intestine. Its low calcemic and phosphatemic properties may result from the decreased endogenous 1,25-(OH)2D3 levels that lead to a reduction in intestinal VDR. This selectivity makes this analog ideal for the treatment of secondary hyperparathyroidism.