Apoprotein-B binding sites in estrogen-treated rabbit liver: quantitative immunoelectron microscopy.
Normal and estrogen-treated rabbit livers were perfused with iodinated very low density lipoproteins (125I-VLDL) and binding and cellular distribution of apolipoprotein (Apo)-B rich lipoproteins in hepatocytes was analyzed using quantitative immunoelectron microscopic and autoradiographic techniques. Apo-B containing particles were bound to and internalized through the formation of endocytotic pits and vesicles with considerably more binding to estrogen-treated specimens (2-fold). Thus, estrogen treatment stimulates Apo-B binding and subsequent internalization of the Apo-B containing particles by increasing the number of endocytotic pits. In contrast to the estrogen induced liver distribution change of Apo-E reported previously, the Apo-B distribution was not changed due to estrogen treatment.
D000818:Animals; D001055:Apolipoproteins B / Q000378:metabolism*; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D005779:Immunodiffusion; D007124:Immunoenzyme Techniques; D008099:Liver / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism*; D018110:Receptors, Lipoprotein
D001055:Apolipoproteins B; D011956:Receptors, Cell Surface; D018110:Receptors, Lipoprotein; C032531:apolipoprotein B,E receptor; D004958:Estradiol; C007630:estradiol 17 beta-cypionate