In addition, significant increases in serum AhR activity and Cyp1a1 mRNA level in the aorta and heart were detected in both 5/6 nephrectomy-induced CKD mice and mice injected with IS for 5 consecutive days, whereas increased Cyp1a1 mRNA level was not observed in AhR knockout mice [89]. This evidence concerns the gene CYP1A1 and chronic kidney disease.