Contribution of liver and skeletal muscle to alanine and lactate metabolism in humans

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

OSTI ID:6071738

Consoli, A; Nurjhan, N; Reilly, Jr, J J; Bier, D M; Gerich, J E ^[1]

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1. Univ. of Pittsburgh School of Medicine, PA (USA)

To quantitate alanine and lactate gluconeogenesis in postabsorptive humans and to test the hypothesis that muscle is the principal source of these precursors, we infused normal volunteers with (3-14C)lactate, (3-13C)alanine, and (6-3H)glucose and calculated alanine and lactate incorporation into plasma glucose corrected for tricarboxylic acid cycle carbon exchange, the systemic appearance of these substrates, and their forearm fractional extraction, uptake, and release. Forearm alanine and lactate fractional extraction averaged 37 +/- 3 and 27 +/- 2%, respectively; muscle alanine release (2.94 +/- 0.27 mumol.kg body wt-1.min-1) accounted for approximately 70% of its systemic appearance (4.18 +/- 0.31 mumol.kg body wt-1.min-1); muscle lactate release (5.51 +/- 0.42 mumol.kg body wt-1.min-1) accounted for approximately 40% of its systemic appearance (12.66 +/- 0.77 mumol.kg body wt-1.min-1); muscle alanine and lactate uptake (1.60 +/- 0.7 and 3.29 +/- 0.36 mumol.kg body wt-1.min-1, respectively) accounted for approximately 30% of their overall disappearance from plasma, whereas alanine and lactate incorporation into plasma glucose (1.83 +/- 0.20 and 4.24 +/- 0.44 mumol.kg body wt-1.min-1, respectively) accounted for approximately 50% of their disappearance from plasma. We therefore conclude that muscle is the major source of plasma alanine and lactate in postabsorptive humans and that factors regulating their release from muscle may thus exert an important influence on hepatic gluconeogenesis.

• OSTI ID: 6071738
• Journal Information: American Journal of Physiology; (USA), Vol. 259:5 Pt 1; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ALANINES
METABOLISM
GLUCOSE
LACTATES
CARBON 13
CARBON 14 COMPOUNDS
MAN
MUSCLES
PRECURSOR
REDOX REACTIONS
SKELETON
TRACER TECHNIQUES
ALDEHYDES
AMINO ACIDS
ANIMALS
BODY
CARBOHYDRATES
CARBON ISOTOPES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
EVEN-ODD NUCLEI
HEXOSES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
MAMMALS
MONOSACCHARIDES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PRIMATES
SACCHARIDES
STABLE ISOTOPES
VERTEBRATES
550501* - Metabolism- Tracer Techniques