Palmitate uptake by hepatocyte suspensions: effect of albumin.
The clearance ratio test has been used to determine whether hepatocytes isolated from female rat livers facilitate the dissociation rate of albumin-palmitate complexes. This test requires knowledge of the clearance rate and unbound palmitate fraction at two protein concentrations. The unbound fractions have been estimated using the heptane-water partition ratio method. These fractions were determined to deviate from the expected linear relationship because of radiolabeled impurities that were still present after purification of the [3H]palmitic acid. With the use of experimentally determined partition ratio values, the palmitate clearance ratios were statistically greater than those predicted by the diffusion-reaction model at albumin concentration combinations above 99 microM/49 microM. Experimental clearance rates also exceeded those predicted by the diffusion-reaction model, but only at albumin concentrations greater than 198 microM. These data support the proposal that hepatocytes facilitate the dissociation of albumin-palmitate complexes at high albumin concentrations.
Burczynski
F J
FJ
Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Canada.
Cai
Z S
ZS
D000818:Animals; D004058:Diffusion; D005260:Female; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008954:Models, Biological; D009994:Osmolar Concentration; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012709:Serum Albumin / Q000378:metabolism / Q000494:pharmacology*
D010169:Palmitic Acids; D012709:Serum Albumin; D019308:Palmitic Acid