Acetate and Formate Uptake into Vesicles Isolated from the Basolateral Region of the Plasma Membrane of Ovine Parotid Acinar Cells

The transport of acetate and formate into plasma membrane vesicles derived from the basolateral face of the ovine parotid acinar cell has an absolute requirement for an anion to be present within the intravesicular space: bicarbonate, formate, acetate, propionate, and butyrate support the uptake of...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 1999-06, Vol.259 (3), p.606-610
Main Authors: Nguyen, Ha-Van, Beechey, R.Brian
Format: Article
Language:English
Subjects:
Acetates - metabolism
Animals
anions
Anions - metabolism
Cell Membrane - metabolism
Enzyme Inhibitors - pharmacology
Ethylmaleimide - pharmacology
Formates - metabolism
Hydrogen-Ion Concentration
Kinetics
metabolizable energy
nutrient transport
Osmolar Concentration
parotid gland
Parotid Gland - metabolism
physiological transport
Potassium Channels - metabolism
ruminants
Sheep
Time Factors
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Summary:The transport of acetate and formate into plasma membrane vesicles derived from the basolateral face of the ovine parotid acinar cell has an absolute requirement for an anion to be present within the intravesicular space: bicarbonate, formate, acetate, propionate, and butyrate support the uptake of either acetate or formate. A pH gradient across the vesicle membrane, pHi 7.4, pH0 5.5, enhances the uptake of formate, but not acetate. There is no direct relationship between the rate of exchange and the degree of protonation of formate or acetate in the extravesicular medium. The process is saturable and can be inhibited by a range of functional group reagents. When mannitol is the main external osmoticum, the uptake of acetate and formate is still rapid; thus, no other ions are involved in the process apart from the external formate or acetate and the intravesicular anion. This activity could play a major role in the provision of energy in ruminant tissues.
ISSN:0006-291X
1090-2104
DOI:10.1006/bbrc.1999.0785