Intrarenal aldosterone has not been examined, although assessment of renal 11β‐HSD activity has been attempted by urinary cortisol–cortisone ratio measurement; cats with CKD had a lower ratio, not supportive of the hypothesis that decreased excretion of active glucocorticoid may potentially reflect excessive MR stimulation in this population (Walker, Elliott, & Syme, 2009). This evidence concerns the gene NR3C2 and chronic kidney disease.