The relationship between gluconeogenic substrate supply and glucose production in humans

Journal Article · Thu Feb 01 04:00:00 EST 1990 · American Journal of Physiology; (USA)

OSTI ID:6995001

Jahoor, F; Peters, E J; Wolfe, R R ^[1]

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1. Shriners Burns Institute, Galveston, TX (USA)

The relationship between gluconeogenic precursor supply and glucose production has been investigated in 14-h and 86-h fasted humans. In protocols 1 and 2 (6,6-2H)glucose and (15N2)urea were infused to measure glucose and urea production rates (Ra) in response to infusions of glycerol and alanine. In protocol 3 first (15N)alanine, (3-13C)lactate, and (6,6-2H)glucose were infused before and during administration of dichloroacetate (DCA) to determine the response of glucose Ra to decreased fluxes of pyruvate, alanine, and lactate, then alanine was infused with DCA and glucose Ra measured. After a 14-h fast, neither alanine nor glycerol increased glucose Ra. Basal glucose Ra decreased by one-third after 86 h of fasting, yet glycerol and alanine infusions had no effect on glucose Ra. Glycerol always reduced urea Ra (P less than 0.05), suggesting that glycerol competitively inhibited gluconeogenesis from amino acids. DCA decreased the fluxes of pyruvate, alanine (P less than 0.01), and glucose Ra (P less than 0.01), which was prevented by alanine infusion. These findings suggest that (1) the reduction in glucose Ra after an 86-h fast is not because of a shortage of gluconeogenic substrate; (2) nonetheless, the importance of precursor supply to maintain basal glucose Ra is confirmed by the response to DCA; (3) an excess of one gluconeogenic substrate inhibits gluconeogenesis from others.

• OSTI ID: 6995001
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 258; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALANINES
ALCOHOLS
ALDEHYDES
AMIDES
AMINO ACIDS
ANIMALS
BIOSYNTHESIS
CARBOHYDRATES
CARBON 13
CARBON ISOTOPES
CARBONIC ACID DERIVATIVES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
EVEN-ODD NUCLEI
FASTING
GLUCOSE
GLYCEROL
HEXOSES
HOMEOSTASIS
HORMONES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INSULIN
ISOTOPE APPLICATIONS
ISOTOPES
KETO ACIDS
LACTATES
LIGHT NUCLEI
MAMMALS
MAN
MONOSACCHARIDES
NITROGEN 15
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PEPTIDE HORMONES
PRIMATES
PYRUVIC ACID
SACCHARIDES
STABLE ISOTOPES
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UREA
VERTEBRATES