Measurement of L-(1-/sup 14/C)leucine kinetics in splanchnic and leg tissues in humans. Effect of amino acid infusion

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · Diabetes; (United States)

OSTI ID:6736776

Gelfand, R A; Glickman, M G; Castellino, P; Louard, R J; DeFronzo, R A

Although whole-body leucine flux is widely measured to study body protein turnover in humans, the contribution of specific tissues to the total-body measurement remains unknown. By combining the organ-balance technique with the systemic infusion of L-(1-14C)leucine, we quantitated leucine production and disposal by splanchnic and leg tissues and by the whole body, simultaneously, in six normal men before and during amino acid infusion. At steady state, disposal of arterial leucine by splanchnic and leg tissues was calculated from the percent extraction (E) of L-(1-14C)leucine counts: uptake = E x (Leu)a x flow. Tissue release of cold leucine (from protein turnover) into vein was calculated as the difference between leucine uptake and the net tissue leucine balance. In the postabsorptive state, despite substantial (P less than .01) extraction of L-(1-14C)leucine by splanchnic (23 +/- 1%) and leg (18 +/- 2%) tissues, net leucine balance across both tissue beds was small, indicating active simultaneous disposal and production of leucine at nearly equivalent rates. Splanchnic tissues accounted for approximately 50% of the measured total-body leucine flux. During amino acid infusion, the net leucine balance across splanchnic and leg tissues became positive, reflecting not only an increase in leucine uptake but also a marked suppression (by approximately 50%, P less than .02) of cold leucine release. This reduction in splanchnic and leg leucine release was indicated by a sharp decline in whole-body endogenous leucine flux.

• Research Organization: Yale Univ. School of Medicine, New Haven, CT (USA)
• OSTI ID: 6736776
• Journal Information: Diabetes; (United States), Journal Name: Diabetes; (United States) Vol. 37:10; ISSN DIAEA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMINO ACIDS
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
DISTRIBUTION
GLUCOSE
HEXOSES
HORMONES
INSULIN
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LEUCINE
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
REACTION KINETICS
SACCHARIDES
SYNTHESIS
TISSUE DISTRIBUTION
TRACER TECHNIQUES