Our group has developed a model for lipid transport between blood and tissue by lateral movement in a continuum of cell membranes. We recently tested this hypothesis in adipose tissue and heart from suckling rats. Morphological findings in adipose tissue demonstrated continuity of intracellular and plasma membranes in endothelial and fat cells, and intercellular contacts between these cells. Biochemical studies showed that both chylomicron and cell triacylglycerol were hydrolyzed in glutaraldehyde-fixed adipose tissue when incubated at 25 C, and morphological studies showed that spiralling bilayered lamellae developed along the continuum between capillaries and fat cells. Morphometric analyses showed that lamellae developed first in capillaries and last in fat cells in adipose tissue from chylomicron-injected fed rats, whereas they developed first in fat cells and last in capillaries in tissue from fasted rats. We concluded lipolytic products formed in fixed tissues move laterally in a continuum of cell membranes to sites where they form lamellae as extensions of the continuum and thereby mark the route proposed for lipid transport between blood and tissue.
NIH ExPorter
NIH ExPorter