Biochemical and ultrastructural analysis of. beta. -VLDL and AC-LDL metabolism by pigeon monocyte-derived macrophages in culture
It is proposed that monocyte-derived foam cells in atherosclerotic lesions of White Carneau pigeons become lipid-filled through the uptake of lipoproteins including ..beta..-migrating very low density lipoproteins (..beta..-VLDL) and acetylated low density lipoproteins (Ac-LDL). Using iodinated forms of the above lipoproteins, specific and saturable receptors for both ..beta..-VLDL and Ac-LDL were detected on the surface of White Carneau pigeon monocyte-derived macrophages in culture. Competition studies demonstrated the high degree of binding specificity for /sup 125/I-Ac-LDL. Likewise, binding of /sup 125/I-..beta..-VLDL to its receptor was significantly inhibited by excess ..beta..-VLDL, however LDL from both hyper- and normocholesterolemic pigeons were also recognized by the receptor. Upon binding of ..beta..-VLDL and Ac-LDL to their respective receptors, the lipoproteins were rapidly internalized and delivered to intracellular sites of degradation. As measured by the amount of /sup 14/C-oleate incorporated into cholesteryl /sup 14/C-oleate, the cholesterole liberated from the degradation of both ..beta..-VLDL and Ac-LDL stimulated cholesteryl ester synthesis in the pigeon cells. Using lipoproteins conjugated to colloidal gold of visualization with transmission electron microscopy, a major difference in the binding and uptake properties of ..beta..-VLDL-Gold and Ac-LDL-Gold was documented.
- Research Organization:
- Wake Forest Univ., Winston-Salem, NC (USA)
- OSTI ID:
- 6905441
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
BIRDS
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHEMISTRY
COMPLEXES
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON MICROSCOPY
GOLD COMPLEXES
IN VITRO
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLED COMPOUNDS
LIPIDS
LIPOPROTEINS
MACROPHAGES
METABOLISM
MICROSCOPY
MONOCARBOXYLIC ACIDS
MORPHOLOGICAL CHANGES
NUCLEI
ODD-EVEN NUCLEI
OLEIC ACID
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHAGOCYTES
PROTEINS
RADIOISOTOPES
SOMATIC CELLS
TRANSITION ELEMENT COMPLEXES
TRANSMISSION ELECTRON MICROSCOPY
ULTRASTRUCTURAL CHANGES
UPTAKE
VERTEBRATES