Supplementation with soy isoflavones together with inulin was associated with decreased renal medullary AQP2 expression and decreased renal medullary AVPR2 expression in non-diabetic animals, whereas in rats with induced type 2 diabetes, such supplementation caused a significant increase in renal medullary AQP2 expression compared to diabetic control animals. This evidence concerns the gene AQP2 and type 2 diabetes mellitus.