During diabetic kidney disease induced by STZ injection in male rats, alpha 2u-globulin nephropathy was predominately observed in association with upregulation of renal water channel membrane proteins (AQP-1, − 2, − 4 and − 5), mitochondrial energetic maintenance protein (HDHD-3) and mitochondrial apoptotic protein (NDUFS-1). Here, AQP1 is linked to diabetic kidney disease.