title: The urinary concentrating mechanism: advances and unsolved problems.
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D006801:Humans; D007684:Kidney Tubules / Q000502:physiology*; D008138:Loop of Henle / Q000502:physiology*; D008954:Models, Biological; D051381:Rats; D012965:Sodium Chloride / Q000378:metabolism; D014508:Urea / Q000378:metabolism*
chemical_list: D012965:Sodium Chloride; D014508:Urea