Hepatic glycogen in humans. II. Gluconeogenetic formation after oral and intravenous glucose

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · American Journal of Physiology; (USA)

OSTI ID:5477536

Radziuk, J ^[1]

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1. Univ. of Western Ontario, London (Canada)

The amount of glycogen that is formed by gluconeogenetic pathways during glucose loading was quantitated in human subjects. Oral glucose loading was compared with its intravenous administration. Overnight-fasted subjects received a constant infusion or (3-{sup 3}H)glucose and a marker for gluconeogenesis, (U-{sup 14}C)lactate or sodium ({sup 14}C)bicarbonate ({sup 14}C)bicarbonate. An unlabeled glucose load was then administered. Postabsorptively, or after glucose infusion was terminated, a third tracer ((6-{sup 3}H)glucose) infusion was initiated along with a three-step glucagon infusion. Without correcting for background stimulation of ({sup 14}C)glucose production or for dilution of {sup 14}C with citric acid cycle carbon in the oxaloacetate pool, the amount of glycogen mobilized by the glucagon infusion that was produced by gluconeogenesis during oral glucose loading was 2.9 +/- 0.7 g calculated from (U-{sup 14}C)-lactate incorporation and 7.4 +/- 1.3 g calculated using ({sup 14}C)bicarbonate as a gluconeogenetic marker. During intravenous glucose administration the latter measurement also yielded 7.2 +/- 1.1 g. When the two corrections above are applied, the respective quantities became 5.3 +/- 1.7 g for (U-{sup 14}C)lactate as tracer and 14.7 +/- 4.3 and 13.9 +/- 3.6 g for oral and intravenous glucose with ({sup 14}C)bicarbonate as tracer (P less than 0.05, vs. ({sup 14}C)-lactate as tracer). When (2-{sup 14}C)acetate was infused, the same amount of label was incorporated into mobilized glycogen regardless of which route of glucose administration was used. Comparison with previous data also suggests that {sup 14}CO{sub 2} is a potentially useful marker for the gluconeogenetic process in vivo.

• OSTI ID: 5477536
• Journal Information: American Journal of Physiology; (USA), Vol. 257; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
GLUCOSE
METABOLISM
GLYCOGEN
BIOSYNTHESIS
ACETATES
ACID CARBONATES
BIOLOGICAL MARKERS
BIOLOGICAL PATHWAYS
BLOOD
CARBON 14 COMPOUNDS
DIET
FASTING
INTRAVENOUS INJECTION
ISOTOPE DILUTION
LACTATES
LIVER
MAN
ORAL ADMINISTRATION
TRITIUM COMPOUNDS
ALDEHYDES
ANIMALS
BIOLOGICAL MATERIALS
BODY
BODY FLUIDS
CARBOHYDRATES
CARBOXYLIC ACID SALTS
DIGESTIVE SYSTEM
GLANDS
HEXOSES
HYDROGEN COMPOUNDS
INJECTION
INTAKE
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANS
POLYSACCHARIDES
PRIMATES
SACCHARIDES
SYNTHESIS
TRACER TECHNIQUES
VERTEBRATES
550501* - Metabolism- Tracer Techniques