Abstract: A bioartificial renal tubule is provided that forms an artificial kidney together with a bioartificial glomerulus suitable for continuous hemofiltration. The bioartificial renal tubule includes an artificial membrane having an inner surface coated with renal tubular epithelial cells and a vessel containing the artificial membrane. The cells are prevented by the use of a MEK inhibitor from being stratified and therefore form a confluent monolayer on the artificial membrane. The renal tubular epithelial cells are characterized in that the contact inhibition thereof is maintained by the use of the MEK inhibitor. The MEK inhibitor is preferably U0126. The attachment of cells capable of reproducing the function of a kidney allows dialysis to be continuously performed for 24 hours with high efficiency and also allows the ability of a renal tubule to reabsorb useful substances to be achieved.