Effects of ethanol on alanine metabolism in perfused mouse liver studied by /sup 13/C NMR
- Bell Laboratories, Murray Hill, NJ
Time courses of /sup 13/C labeling from alanine and ethanol in perfused mouse livers have been followed by NMR. The enrichment at specific carbons of glucose, glutamate, glutamine, aspartate, acetate, acetoacetate, ..beta..-hydroxybutyrate, and lactate has been measured. The specific labeling of glutamate in the presence of labeled alanine and labeled or unlabeled ethanol shows that, under these conditions, alanine enters the tricarboxylic acid cycle almost exclusively through pyruvate carboxylation, whereas ethanol is the exclusive source of acetyl-CoA. In the absence of ethanol, the alanine label flows through both paths. By comparing the scrambling of /sup 13/C between C3 and C2 of glutamate it is possible to estimate the mitochondrial fumarase activity; the C6-to-C5 ratios in glucose give the additional scrambling by cytosolic fumarase activity. In addition, the C6-to-C1 and C5-to-C2 ratios in glucose show that there is about 15% flux through the pentose cycle. Finally, the C4-to-C2 ratios in glutamine and glutamate are unequal at any time (the glutamine labels reflect the label distribution in glutamate measured 1 hr earlier), providing a method for studying flow through glutamine synthetase in situ.
- OSTI ID:
- 5414988
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 76:10
- Country of Publication:
- United States
- Language:
- English
Similar Records
/sup 13/C NMR study of effects of fasting and diabetes on the metabolism of pyruvate in the tricarboxylic acid cycle and of the utilization of pyruvate and ethanol in lipogenesis in perfused rat liver
Path of carbon flow during NO/sub 3//sup -/-induced photosynthetic suppression in N-limited Selenastrum minutum
Related Subjects
ALANINES
METABOLISM
ETHANOL
BIOLOGICAL EFFECTS
CARBON 13
KREBS CYCLE
LABELLED COMPOUNDS
LIVER
METABOLITES
MICE
NUCLEAR MAGNETIC RESONANCE
PERFUSED ORGANS
RESPONSE MODIFYING FACTORS
ALCOHOLS
AMINO ACIDS
ANIMALS
BODY
CARBON ISOTOPES
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
EVEN-ODD NUCLEI
GLANDS
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MAMMALS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
RESONANCE
RODENTS
STABLE ISOTOPES
VERTEBRATES
550501* - Metabolism- Tracer Techniques
550201 - Biochemistry- Tracer Techniques