Metabolism of (2-14C)acetate and its use in assessing hepatic Krebs cycle activity and gluconeogenesis
- Case Western Reserve University, Cleveland, OH (USA)
To examine the fate of the carbons of acetate and to evaluate the usefulness of labeled acetate in assessing intrahepatic metabolic processes during gluconeogenesis, (2-14C)acetate, (2-14C)ethanol, and (1-14C)ethanol were infused into normal subjects fasted 60 h and given phenyl acetate. Distributions of 14C in the carbons of blood glucose and glutamate from urinary phenylacetylglutamine were determined. With (2-14C)acetate and (2-14C)ethanol, carbon 1 of glucose had about twice as much 14C as carbon 3. Carbon 2 of glutamate had about twice as much 14C as carbon 1 and one-half to one-third as much as carbon 4. There was only a small amount in carbon 5. These distributions are incompatible with the metabolism of (2-14C)acetate being primarily in liver. Therefore, (2-14C)acetate cannot be used to study Krebs cycle metabolism in liver and in relationship to gluconeogenesis, as has been done. The distributions can be explained by: (a) fixation of 14CO2 from (2-14C)acetate in the formation of the 14C-labeled glucose and glutamate in liver and (b) the formation of 14C-labeled glutamate in a second site, proposed to be muscle. (1,3-14C)Acetone formation from the (2-14C)acetate does not contribute to the distributions, as evidenced by the absence of 14C in carbons 2-4 of glutamate after (1-14C)ethanol administration.
- OSTI ID:
- 5643929
- Journal Information:
- Journal of Biological Chemistry; (USA), Vol. 266:11; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACETATES
METABOLISM
LIVER
CARBON 14 COMPOUNDS
ETHANOL
FASTING
GLUCOSE
GLUTAMIC ACID
ISOTOPE DILUTION
UREA
ALCOHOLS
ALDEHYDES
AMIDES
AMINO ACIDS
BODY
CARBOHYDRATES
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
GLANDS
HEXOSES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
SACCHARIDES
TRACER TECHNIQUES
550501* - Metabolism- Tracer Techniques