ABSTRACT
Fatty acids (FA) are critical to the maintenance of physiological homeostasis. They are a major source of energy, provide essential building blocks of membrane structure, and play a variety of normal and pathologic modulatory functions. The FA produced by the activity probably binds to a cytosolic FA binding protein (FABP) and is then transferred via the aqueous phase to the plasma membrane. Once in the inner hemileaflet of the membrane, the FA is transported to the outer leaflet, where it can leave the membrane and enter the aqueous interstitial fluid surrounding the adipocyte. Understanding FA transport across lipid bilayers is clearly essential for a complete understanding of transport across biologic membranes. In order to overcome the technical limitations of tracer measurements, a number of studies have been done using fluorescently labeled FA. Transfer of oleate from small unilamellar vesicles composed of dimyristoylphosphatidylcholine to albumin was detected by the quenching, upon FA binding, of albumin tryptophan fluorescence.
