RBP4 and chronic kidney disease: In addition to these features of CKD, 5/6Nx wild-type mice exhibited high blood pressure (P < 0.01) and increased serum levels of angiotensin II, aldosterone (P < 0.01 for angiotensin II, P < 0.01 for aldosterone, respectively; Fig. 1a), creatinine, urea nitrogen (P < 0.01 for creatinine, P < 0.01 for urea nitrogen, respectively; Supplementary Fig. 1a), retinol, and RBP4 (P < 0.01 for retinol, P < 0.01 for RBP4, respectively; Supplementary Fig. 1b).