THE AQUAPORIN FAMILY OF WATER CHANNELS IN KIDNEY - AN UPDATE ON PHYSIOLOGY AND PATHOPHYSIOLOGY OF AQUAPORIN-2

The long-standing problem of membrane water transport has been advance d by the recognition of a new family of water transport proteins, the ''aquaporins'' [1-3]. Not surprisingly, water transport is a major pro cess in kidney physiology, and the biology of aquaporins is most thoro ughly understood in that organ. We reviewed in detail the status of aq uaporins in the kidney only one year ago [4], but the subsequent progr ess has dictated the need for an update. This seems especially appropr iate in honor of the 100th birthday of Homer Smith, the pioneer whose foresight initiated this field.