It is highly unlikely that reduced Pendrin expression is the primary cause of polyuria in Vhl-deficient mice as it has been shown that knockout of Pendrin in the mouse kidney can be compensated by NCC activity [28] and mRNA and protein expression of NCC in VhlΔ/Δ kidneys is unaltered (Figure 2B and 2C). This evidence concerns the gene SLC26A4 and Polyuria.