Sinusoidal endothelial endocytosis of low density lipoprotein-gold conjugates in perfused livers of ethinyl-estradiol treated rats.
We examined endocytosis of low-density lipoproteins (LDL) conjugated to colloidal gold by the sinusoidal endothelium in perfused livers of 17 alpha-ethinyl estradiol-treated rats. After 15 min of perfusion, the gold-LDL was randomly bound at the endothelial surface, but internalized only at coated pits. Uptake of the conjugate was to electron-lucid vacuoles. After 1 h of perfusion, there was a progressive accumulation of gold in organelles resembling lysosomes, with further accumulation seen at 2 h perfusion. Uptake of the conjugate was equivalent to the rate of 125I-LDL and competitively inhibited by a 20-fold excess of free LDL. These results suggest that a specific endocytotic pathway for LDL is present in the sinusoidal endothelium in the estrogen-hypolipidemic state.
Handley
D A
DA
Department of Physiology, College of Physicians and Surgeons, Columbia University, New York, N.Y./USA.
Arbeeny
C M
CM
Chien
S
S
D000818:Animals; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D004705:Endocytosis; D004727:Endothelium / Q000378:metabolism*; D045166:Estradiol Congeners / Q000494:pharmacology; D004997:Ethinyl Estradiol / Q000494:pharmacology; D017979:Gold Colloid / Q000378:metabolism; D006801:Humans; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008099:Liver / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D011973:Receptors, LDL / Q000378:metabolism*; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism
D045166:Estradiol Congeners; D017979:Gold Colloid; D008077:Lipoproteins, LDL; D011973:Receptors, LDL; D004997:Ethinyl Estradiol