Reassessment of sup 14 CO sub 2 compartmentation and of ( sup 14 C)formate oxidation in rat liver

Our previous report had concluded that a fraction of ({sup 14}C)formate oxidation in liver occurs in the mitochondrion. This conclusion was based on the labeling patterns of urea and acetoacetate labeled via {sup 14}CO{sub 2} generated from ({sup 14}C)formate and other ({sup 14}C)substrates. We reas...

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Bibliographic Details
Published in:The Journal of biological chemistry 1989-11, Vol.264:33
Main Authors: Marsolais, C., Lafreniere, F., David, F., Dodgson, S.J., Brunengraber, H.
Format: Article
Language:English
Subjects:
550501 - Metabolism- Tracer Techniques
ACETOACETATES
ALDEHYDES
AMIDES
ANIMALS
BASIC BIOLOGICAL SCIENCES
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CELL CONSTITUENTS
CHALCOGENIDES
DIGESTIVE SYSTEM
ENZYME INHIBITORS
FORMATES
GLANDS
GLUCOSE
HEXOSES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIVER
MAMMALS
METABOLISM
MITOCHONDRIA
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PERFUSED ORGANS
RATS
RODENTS
SACCHARIDES
TRACER TECHNIQUES
UREA
VERTEBRATES
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Summary:Our previous report had concluded that a fraction of ({sup 14}C)formate oxidation in liver occurs in the mitochondrion. This conclusion was based on the labeling patterns of urea and acetoacetate labeled via {sup 14}CO{sub 2} generated from ({sup 14}C)formate and other ({sup 14}C)substrates. We reassessed our interpretation in experiments conducted in (i) perifused mitochondria and (ii) isolated livers perfused with buffer containing ({sup 14}C)formate, ({sup 14}C)gluconolactone, {sup 14}CO{sub 2}, or NaH{sup 13}CO{sub 3}, in the absence and presence of acetazolamide, an inhibitor of carbonic anhydrase. Our data show that the cytosolic pools of bicarbonate and CO{sub 2} are not in isotopic equilibrium when {sup 14}CO{sub 2} is generated in the cytosol or is supplied as NaH{sup 14}CO3. We retract our earlier suggestion of a mitochondrial site of ({sup 14}C)formate oxidation.
ISSN:0021-9258
1083-351X