Understanding of nephron membrane transport systems by means of isolated membranes and cells

Sabine Karam MD
Saint George Hospital University Medical Center, Beirut, Lebanon

Rolf Kinne from the Max Planck Institute of Molecular Physiology and Heini Murer from the University of Zurich made significant contributions to the understanding of transport mechanisms in human epithelial cells and, most notably, in the proximal tubular cells. They used the membrane-molecular approach (1, 2) to isolate intestinal and renal brush-border-membrane vesicles in order to study their transport properties in vitro. Intestinal and renal brush-border membranes were found to contain an Na/H antiport system that catalyzes an electroneutral exchange of Na+ against protons and can subsequently produce a proton gradient in the presence of a concentration difference for Na+. They concluded that there was an active proton secretion in the small intestine and the proximal tubule of the kidney (3). This technique allowed to localize transport elements situated in the two opposite sides of the cell (luminal and basolateral); and to characterize the driving forces, molecular properties, and regulatory influence of these transport elements. They summarized their findings in a seminal paper published in 1980 (4).


  1. Kinne R, Schwartz IL. Isolated membrane vesicles in the evaluation of the nature, localization, and regulation of renal transport processes. Kidney Int. 1978;14(6):547-56. Epub 1978/12/01. doi: 10.1038/ki.1978.163. PubMed PMID: 219287.
  2. Kinne R. Membrane-Cellular aspects of tubular transport. In: K.Thureau, editor. MTP International Review of Sciences Kidney and Urinary Tract Physiology, Vol11. London: Butterworths, Baltimore: University Park Press; 1976. p. 169-210.
  3. Murer H, Hopfer U, Kinne R. Sodium/proton antiport in brush-border-membrane vesicles isolated from rat small intestine and kidney. Biochem J. 1976;154(3):597-604. Epub 1976/03/15. PubMed PMID: 942389; PubMed Central PMCID: PMCPMC1172760.

  4. Murer H, Kinne R. The use of isolated membrane vesicles to study epithelial transport processes. J Membr Biol. 1980;55(2):81-95. Epub 1980/07/15. doi: 10.1007/bf01871151. PubMed PMID: 6997489.

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