Cotransport of water by the Na~+/glucose cotransporter

摘要

Water is transported across epithelial mem- branes in the absence of any hydrostatic or osmotic gradients. A prime example is the small intestine, where 10 liters of water are absorbed each day. Although water absorption is second- ary to active solute transport, the coupling mechanism be- tween solute and water flow is not understood. We have tested the hypothesis that water transport is directly linked to solute transport by cotransport proteins such as the brush border Na~+/glucose cotransporter.