Abstract:
:Classically, there is a direct correlation between the lipophilic nature of a molecule and its rate of permeation across a biological membrane, so cell membranes should be more permeable to small, neutral molecules than they are to charged molecular species of similar size. Consequently, the distribution of NH+4 in biological systems is generally believed to be due to the rapid diffusion and equilibration of lipophilic NH3 across cell membranes and the accumulation of NH+4 to be governed by pH differences between compartments. Here we report that renal tubule cells from the medullary thick ascending limb of Henle have an apical membrane which is not only virtually impermeable to NH3, but is also highly permeable to NH+4. These remarkable properties have been incorporated into a model which explains how this renal epithelium can mediate vectorial movement of NH+4 between compartments of equal pH.
journal_name
Naturejournal_title
Natureauthors
Kikeri D,Sun A,Zeidel ML,Hebert SCdoi
10.1038/339478a0subject
Has Abstractpub_date
1989-06-08 00:00:00pages
478-80issue
6224eissn
0028-0836issn
1476-4687journal_volume
339pub_type
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