New insights into gill epithelial transport: Linking ammonia excretion and sodium uptake
Abstract
Models of gill epithelial transport are rapidly changing as researchers discover more complex and
specialized cell types and use genomic data to uncover completely new protein transporters. Maetz and
Garcia Romeu (1964) first suggested a linkage between ammonia excretion and active Na+ uptake at the
gills of freshwater animals. Although many studies have provided supporting evidence for such a
linkage, only in the last 4 years with the discovery of ammonia-transporting Rhesus (Rh) glycoproteins in
gill tissue have we been able to more fully understand the model of gill ammonia transport in freshwater
animals. Recent evidence supports an apical “Na+/NH4
+ exchange complex” consisting of several
membrane transporters (Rhcg, V type H+ATPase, Na+/H+ exchanger (NHE 2/3, Na+ channel) working
together as a metabolon providing an acid-trapping mechanism for apical excretion in freshwater fish.
The model for gill ammonia transport in seawater is more controversial, although Rhcg also appears to be
associated with Na+ transport.
Description
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Abstract
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Keywords
AMMONIA, FRESHWATER ANIMALS, MEMBRANE TRANSPORT PROTEINS, SODIUM
Citation
Wright, P. A., Wood, C. M., & Cooper, C. A. (2011). New insights into gill epithelial transport: Linking ammonia excretion and sodium uptake. Proceedings of the 8th International Congress of Comparative Physiology and Biochemistry.