Direct determination of free fatty acid transport across the adipocyte plasma membrane using quantitative fluorescence microscopy.
Movement of free fatty acids (FFA) across the plasma membrane has been directly measured for the first time, using fluorescent FFA analogs and quantitative fluorescence microscopy. The rate of short chain FFA (less than or equal to 12 carbons) transport from the extracellular medium into intracellular lipid droplets of 3T3F442A adipocytes was more than 40-fold faster than long chain FFA (16 and 18 carbons). The membrane-impermeable amino reagent 4,4'-diisothiocyanostilbene-2,2'-disulfonate, inhibited greater than or equal to 50% of the long chain FFA transport but had no effect on short chain FFA transport. Oleic acid (2 microM) inhibited 90% of the fluorescent oleate transport but had no effect on the 11-carbon analog. These results indicate that a large fraction of long chain FFA uptake is mediated by a plasma membrane protein (s).
Storch
J
J
Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts 02115.
Lechene
C
C
Kleinfeld
A M
AM
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods
D005230:Fatty Acids, Nonesterified; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid