Effect of 1,25-dihydroxyvitamin D3 on osteopenia induced by prednisolone in adult rats

Summary Adult male rats were fed a diet containing 0.15% calcium, 0.3% phosphorus, and either 100, 50, or 20 mg of prednisolone per kg of diet. All these levels of prednisolone led to osteopenia, decreased intestinal absorption of calcium, slightly lower serum calcium and phosphorus, and a decreased level of serum 1,25-dihydroxyvitamin D₃. Exogenous parenteral 1,25-dihydroxyvitamin D₃ corrected steroid-induced changes in serum calcium and phosphorus, but could not completely correct the low intestinal calcium transport; nor did it prevent the development of osteopenia. The prednisolone-induced osteopenia seems at least in part to be caused by impaired intestinal calcium transport. The impaired calcium transport may be the result of low levels of 1,25-dihydroxyvitamin D₃ and a direct effect of presnisolone on the intestine. No reprints of this article will be available from the authors.