Determination of pathways of glycogen synthesis and the dilution of the three-carbon pool with (U- sup 13 C)glucose

Journal Article · Thu Mar 14 23:00:00 EST 1991 · Proceedings of the National Academy of Sciences of the United States of America; (United States)

DOI:https://doi.org/10.1073/pnas.88.6.2103· OSTI ID:5030414

Katz, J; Wals, P A ^[1]; Lee, W N.P. ^[2]

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1. Cedars-Sinai Medical Center, Los Angeles, CA (United States)
2. Los Angeles Research and Education Inst., Torrance, CA (United States)

Rats were infused with glucose at 30 mg/min, containing 18% enriched (U-{sup 13}C)glucose and (1-{sup 14}C)- and (3-{sup 3}H)glucose and liver glycogen were determined by gas chromatography/mass spectroscopy. The contribution of the direct pathway to glycogen was calculated from the three tracers, and the values by all three were nearly identical, about 50%. The {sup 14}C specific activity in carbon 6 of glycogen glucose was about 6% that of carbon 1. The ({sup 3}H)glucose/(1-{sup 14}C)glucose ratio in glycogen was 80-90% that is blood glucose. The enrichment of {sup 13}C and the specific activity of {sup 14}C in glycogen formed by the indirect path were 20-25% of glycogen formed directly from glucose. The dilution is of two kinds: (1) an exchange of labeled carbon with unlabeled carbon in the tricarboxylic acid cycle and (2) dilution by unlabeled nonglucose carbon. Methods to calculate the two types of dilution are presented. In rate preinjected with glucagon, the dilution through the tricarboxylic acid cycle was unaffected but that by nonglucose carbon was decreased.

• OSTI ID: 5030414
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (United States), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (United States) Vol. 88:6; ISSN PNASA; ISSN 0027-8424
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
BODY
CARBOHYDRATES
CARBON 13
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON ISOTOPES
CHROMATOGRAPHY
DIGESTIVE SYSTEM
EVEN-ODD NUCLEI
GAS CHROMATOGRAPHY
GLANDS
GLUCOSE
GLYCOGEN
GLYCOLYSIS
HEXOSES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LABELLED POOL TECHNIQUES
LIGHT NUCLEI
LIVER
MAMMALS
MASS SPECTROSCOPY
METABOLISM
MONOSACCHARIDES
NUCLEI
ORGANIC COMPOUNDS
ORGANS
POLYSACCHARIDES
RATS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES