ISSN:
0263-6484
Keywords:
Jejunum
;
ATPase activities
;
sodium transport
;
basolateral membrane vesicles
;
everted intestine
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
The basolateral membrane of the jejunal enterocyte of the rat was separated by self-orienting Percoll-gradient centrifugation and further purified from brush border contamination. Pellets were analysed for Mg-, Na- and (Na, K)-ATPase activities. The uptake of 0·02 M NaCl was also followed by the rapid micro-filtration technique. Transintestinal transport of fluid and electrolytes, and cell water, Na and K were determined in the in vitro everted and incubated jejunum.There is ouabain-insensitive Na-ATPase in addition to the well-known (Na, K)-ATPase in the basolateral membrane. These are differently inhibited by furosemide and ethacrynate. Na uptake by osmotically active basolateral membrane vesicles is enhanced by ATP and a further enhancement is obtained if there is intravesicular K. The ATP effect is inhibited differently by strophanthidin, furosemide and ethacrynate. In the everted sac preparation, transintestinal transport of Na and fluid still occurs when the Na/K pump is totally inhibited by ouabain.These experimental results suggest that there is also a ouabain-insensitive Na pump, different from the Na/K pump, in the basolateral membrane.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cbf.290060303
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