VDR and Hypercalciuria: Similar improvement in BMD and risk of hip fracture has been reported in IH subjects and others whose urine Ca had been lowered by treatment with thiazide diuretics.49, 50, 51, 52 We have shown that the hypercalciuria in the rat model is a polygenic trait53, 54 and there is an increase in vitamin D receptors (VDRs) in bone, intestine, and kidney in the GHS rats compared with SD rats22 that contributes significantly to Ca mobilization in these rats.