Amphibolic role of the Krebs cycle in the insulin-stimulated protein synthesis

Journal Article · Thu Aug 15 00:00:00 EDT 1991 · Archives of Biochemistry and Biophysics; (United States)

DOI:https://doi.org/10.1016/0003-9861(91)90445-O· OSTI ID:5044659

Mohan, C; Memon, R A; Bessman, S P ^[1]

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1. Department of Pharmacology and Nutrition, University of Southern California, School of Medicine, Los Angeles (United States)

It has been a generally held view that insulin does not significantly affect the incorporation of amino acids into liver protein. This interpretation was based on data obtained from studies using the branched chain amino acids, which are poorly metabolized by the hepatic tissue. The effect of insulin on 14CO2 formation and protein incorporation of several 1-14C-labeled or U-14C-labeled amino acids was studied in isolated rat hepatocytes and diaphragm pieces. It was shown that insulin enhanced 14CO2 formation and protein incorporation primarily of those carbons of amino acids which are metabolized through the mitochondrial Krebs cycle. Using aminooxyacetic acid (0.5 mM), a potent inhibitor of the transamination reaction, it was shown that there exists an insulin-sensitive pool of glutamate which is preferentially utilized for protein synthesis in the presence of insulin. The insulin effect on protein incorporation of 14C-labeled glutamate generated in the Krebs cycle was abolished in the presence of aminooxyacetic acid. The authors interpret these results to signify that mitochondrial transamination of alpha-ketoglutarate to glutamate is essential for insulin stimulation of 14C incorporation into hepatocyte protein.

• OSTI ID: 5044659
• Journal Information: Archives of Biochemistry and Biophysics; (United States), Vol. 289:1; ISSN 0003-9861
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
INSULIN
BIOCHEMICAL REACTION KINETICS
PROTEINS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBON DIOXIDE
LIVER
METHIONINE
MITOCHONDRIA
MUSCLES
RATS
TRACER TECHNIQUES
VALINE
AMINO ACIDS
ANIMALS
BODY
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHALCOGENIDES
DIGESTIVE SYSTEM
DRUGS
GLANDS
HORMONES
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIPOTROPIC FACTORS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PEPTIDE HORMONES
REACTION KINETICS
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques