CYP24A1 and chronic kidney disease: Given the excessive toxicity related to reducing kidney Cyp24a1 activity in a mouse model of CKD, we fed VillinCreERT2Cyp24fl/fl mice and their Cre-negative controls a diet containing 0.2% adenine supplemented with 1% calcium and no vitamin D for 2 weeks to induce kidney damage (CKD diet, Figure 7A).