Effect of lipoproteins on cholesterol synthesis in rat Sertoli cells.
Lipoprotein metabolism has been investigated in cultured rat Sertoli cells. Cells incubated with low-density lipoproteins (LDLs) or high-density lipoproteins (HDLs) showed a concentration-dependent decrease of sterol synthesis, indicating a net cholesterol delivery to the Sertoli cells. At 50 micrograms/mL, lipoproteins inhibited the incorporation of [14C]acetate into free cholesterol by 83% for the LDL and 47% for the HDL. Electron microscopic examinations of the Sertoli cells provide evidence of the internalization of gold-labelled HDL into coated pits and coated vesicles. Competitive studies between human LDL and rat HDL indicate that Sertoli cells take up cholesterol from LDL and HDL containing apolipoprotein (apo) E by common pathways. These results suggest that Sertoli cells possess apo B and E receptors for the uptake and degradation of LDL and HDL, although the basement membrane excludes the passage of LDL from blood capillaries to the Sertoli cells. At 50 micrograms/mL, apo-E-depleted HDL inhibited the incorporation of [14C]acetate into free cholesterol by 34%. Thus, this study shows that Sertoli cells are capable of taking up apo-E-depleted HDL cholesterol for cell metabolism.
Maboundou
J C
JC
Laboratoire de Biochimie, Université de Caen, France.
Fofana
M
M
Fresnel
J
J
Bocquet
J
J
Le Goff
D
D
D000085:Acetates / Q000378:metabolism; D000818:Animals; D001057:Apolipoproteins E / Q000502:physiology; D002478:Cells, Cultured; D002784:Cholesterol / Q000096:biosynthesis* / Q000378:metabolism; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism / Q000648:ultrastructure; D018699:Coated Vesicles / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D016253:Microscopy, Immunoelectron; D051381:Rats; D017207:Rats, Sprague-Dawley; D011973:Receptors, LDL / Q000378:metabolism; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism*
D000085:Acetates; D001057:Apolipoproteins E; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D011973:Receptors, LDL; D002784:Cholesterol