Comparison of ascorbate and glucose transport in the heart

Journal Article · Mon Jul 01 04:00:00 EDT 1985 · Am. J. Physiol.; (United States)

OSTI ID:5246920

Bassingthwaighte, J B; Kuikka, J T; Chan, I S; Arts, T; Reneman, R S

Multiple indicator-dilution experiments were done to compare the transcapillary exchange of tracer amounts of L-(/sup 14/C)ascorbate and D-(/sup 3/H)glucose (against an intravascular reference /sup 131/I-albumin) in Ringer-perfused (5 mM glucose) isolated rabbit hearts. The indicator-dilution curves for the two were virtually superimposed over the first 40-80 s. Estimates of the capillary permeability-surface area products, PSc, were the same, 2.3 +/- 0.7 (SD) ml X g-1 X min-1 (n = 18), in accord with the coincidence of their instantaneous extractions. The similarity of glucose and ascorbate permeabilities is explained by the similarity in molecular weights and passive diffusivity, their lipophobic nature, and the paucity of carrier-mediated endothelial transport for either molecule. The data were analyzed via a model composed of aggregates of spatially distributed capillary-tissue units (capillary blood, interstitium, myocytes) accounting for the heterogeneity of regional flows. The interstitial volumes in this preparation are enlarged, 0.30 +/- 0.04 ml/g. There is substantial entry into myocardial cells, the cell permeability-surface area products being approximately 2-3 ml X g-1 X min-1 for ascorbate and glucose. The estimated volumes of interstitial and intracellular space, 0.30 and 0.47 ml X g-1 X min-1, reflect interstitial edema and are very close to measured values, giving reassurance concerning the methods of modeling analysis.

• Research Organization: Univ. of Washington, Seattle
• OSTI ID: 5246920
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States); ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALBUMINS
ALDEHYDES
ANIMAL TISSUES
ANIMALS
ASCORBIC ACID
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD FLOW
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARDIOVASCULAR SYSTEM
COMPARATIVE EVALUATIONS
DAYS LIVING RADIOISOTOPES
ENDOTHELIUM
GLUCOSE
HEART
HEXOSES
INTERMEDIATE MASS NUCLEI
IODINE 131
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANE TRANSPORT
MOLECULAR WEIGHT
MONOSACCHARIDES
MUSCLES
MYOCARDIUM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PERFUSED ORGANS
PERMEABILITY
PROTEINS
RABBITS
RADIOISOTOPES
SACCHARIDES
STRUCTURAL MODELS
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES
VITAMINS