Estimation of transcapillary transport of palmitate by the multiple indicator dilution technique

Conference · Sat Mar 01 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5461368

Little, S E; van der Vusse, G J; Bassingthwaighte, J B

From the outflow concentration-time curves for /sup 14/C-palmitate, intravascular (/sup 131/I-albumin) and extracellular (/sup 3/H-sucrose) tracers, palmitate extraction was estimated in rabbit hearts Langendorff-perfused at a constant flow with nonrecirculated palmitate-albumin Kreb's Ringer buffer. Contamination of /sup 131/I-albumin with free /sup 13/$/sup 1/I/sup -/ (typically 1%) or aggregated albumin (typically 0.1 to 0.5%) greatly alters the shapes of the tails of the curves after 2 albumin transit times, vitiating accurate estimation of cellular permeability or reactions. Buffers were prepared by adding K/sup +/-palmitate (made using K/sub 2/CO/sub 3/) to albumin solutions. The final concentrations (after dialysing twice and filtering through a 1.2 ..mu.. filter) of K/sup +/, HCO/sub 3/, and CO/sub 3/ were 5.0 mM, 23.5 mM and 0.5 mM respectively, pH was between 7.35 and 7.40 for several hours. The bolus of tracers was prepared by mixing /sup 131/I-albumin (dialysed to remove I/sup -/, and filtered through a 0.2 ..mu..M filter to remove aggregates), K/sup +/ (U-/sup 14/C)palmitate (high specific activity) and /sup 3/H-sucrose. Before injection the radioactive bolus is preequilibrated with the perfusate at bolus:perfusate ratio of 1:10. Glacial acetic acid is added to the outflow samples to remove the /sup 14/CO/sub 2/ which, if present in the sample, would be interpreted as increased palmitate back diffusion. The peak extractions of palmitate were about 40% at perfusate palmitate concentrations of 0.02 to 1.0 mM, 0.4 mM albumin, at a flow of 5 mlg/sup -1/ 2)/sup 1/, showing capillary permeability-surface area product to be roughly constant. This suggests either than transcapillary palmitate transport is passive or that a transporter interacts with the albumin-palmitate complex.

• Research Organization: Univ. of Washington, Seattle
• OSTI ID: 5461368
• Report Number(s): CONF-8604222-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:3
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALBUMINS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARDIOVASCULAR SYSTEM
DAYS LIVING RADIOISOTOPES
DISACCHARIDES
HEART
INTERMEDIATE MASS NUCLEI
IODINE 131
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANE TRANSPORT
NUCLEI
ODD-EVEN NUCLEI
OLIGOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PERFUSED ORGANS
PROTEINS
RABBITS
RADIOISOTOPES
SACCHARIDES
SACCHAROSE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES