Lipoprotein lipase and fatty acid transport in heart, adipose tissue and mammary gland: immuno and cytochemistry.
Lipoprotein lipase acts at the luminal surface of capillaries to hydrolyze chylomicron triacylglycerol to fatty acids that are transferred across the capillary wall to tissue cells for reesterification into cellular triacylglycerol. The distribution of lipoprotein lipase in capillaries and the origin of the lipase was studies with electron microscopic immunocytochemistry in heart. Fatty acids are ampipathic molecules and can be visualized as myelin figures in sections and freeze fracture replicas of tissue. We used this cytochemical technique to study fatty acid transport between capillaries and parenchymal cells in adipose tissue perfused with chylomicrons and in adipose tissue stimulated with isoproterenol to hydrolyze intracellular triacylglycerol with. Morphological results in mammary gland indicate that incorporation of chylomicron fatty acids into milk triacylglycerol occurs via transport of fatty acids in membranes leaflets to sites of reesterification. Fatty acids would leave the membrane leaflet when they are reesterified into triacylglycerol to locate within the hydrocarbon domain of intracellular lipid droplets to be sexcreted into milk.
Blanchette-Mackie
E J
EJ
Laboratory of Cellular and Developmental Biology, National Institute of Diabetes, Digestive and Kidney Disease, National Institutes of Health, Bethesda, MD 20892.
D000273:Adipose Tissue / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D005227:Fatty Acids / Q000493:pharmacokinetics*; D005260:Female; D007150:Immunohistochemistry; D008071:Lipoprotein Lipase / Q000493:pharmacokinetics*; D008321:Mammary Glands, Animal / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D008854:Microscopy, Electron; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats
D005227:Fatty Acids; D008071:Lipoprotein Lipase