Analysis of adult kidneys with severe hydronephrosis revealed a decrease of the mRNA abundance of genes expressed in proximal tubular cells (Aqp1, Aqp7, Slc34a1, Slc5a1, Cubn), distal tubular cells (Slc12a3), collecting duct cells (Aqp2, Aqp3) and intercalated cells (Atp6v1b1, Slc26a4), suggesting that the relative number of these cell types may be decreased in VhlΔ/Δ adult kidneys (Figure 2D). This evidence concerns the gene AQP1 and hydronephrosis.