Increased sensitivity to 1,25(OH)2D3 in bone from genetic hypercalciuric rats

Hypercalciuric patients have been suggested to show increased intestinal calcium resorption that leads to enhanced bone resorption. In a model of human hypercalciuria using hypercalciuric Sprague-Dawley rats, the increase in intestinal calcium absorption enhanced bone resorption by acting directly or indirectly through an increase in intestinal 1,25(OH)2D3 receptors (VDR). Exogenous VDR stimulated calcium efflux from hypercalciuric rats by increasing urine calcium excretion.