Calcium-Mobilizing Effect of Large Doses of 25-Hydroxycholecalciferol in Anephric Rats

Henriette Pavlovitch; Michele Garabedian; Sonia Balsan

doi:10.1172/JCI107458

¹Laboratoires des Tissus Calcifiés (Centre National de Recherche Scientifique, équipe de recherche 126) et Unité de Recherches sur les Maladies du Métabolism chez l'enfant (Institut National de Santé et de Recherche Médicale, Unité de Recherche 30), Hôpital des Enfants Malades, Paris, France

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Published in Volume 52, Issue 10 on October 1, 1973
J Clin Invest. 1973;52(10):2656–2659. https://doi.org/10.1172/JCI107458.
© 1973 The American Society for Clinical Investigation

Published October 1, 1973 - Version history

The effect of high doses of 25-hydroxycholecalciferol on plasma calcium concentration was studied in rats receiving a low-calcium normal vitamin D diet. In bilaterally nephrectomized animals, as in sham-operated controls, 62.5 nmol of 25-hyroxycholecalciferol did not produce a rise of plasma calcium concentration. In contrast, the administration of 125 or 625 nmol, doses 1,000-5,000 times the minimal active dose in D-deficient rats, was followed in both groups of animals by a significant increase of plasma calcium concentration. Removal of either parathyroids alone or parathyroid and thyroid glands did not suppress this effect. These data suggest that when large doses are used in vivo, the renal conversion of 25-hydroxycholecalciferol to more polar metabolites is not an obligatory step for its calcium-mobilizing action. The present study does not elucidate, however, the exact mechanism(s) of this effect.

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