Reduction in VLDL, but not HDL, in plasma of rats deficient in choline.
We have analyzed plasma lipoprotein levels in young male rats fed a choline-deficient diet for 3 days. We confirmed previous studies that choline deficiency promotes 6.5-fold accumulation of triacyglycerol in the liver (23.9 +/- 6.0 versus 3.69 +/- 0.92 mumol/g liver) and reduction of triacylglycerol concentration in plasma by 60% (0.17 +/- 0.04 versus 0.46 +/- 0.10 mumol/mL plasma). Agarose gel electrophoresis showed that the plasma very low density lipoprotein (VLDL) levels were reduced in choline-deficient rats, but the concentration of plasma high density lipoproteins (HDL) was not affected. Sodium dodecyl sulfate - polyacrylamide gel electrophoresis of fractionated plasma lipoproteins revealed that the concentrations of apolipoproteins (apo) BH, BL, and E in VLDL from choline-deficient rats were 37.1, 11.0, and 37.2% of normal levels, respectively. In contrast, the amount of apo A-I, the major one in HDL, was almost unchanged. Correspondingly, there were decreased lipid (mainly phosphatidylcholine and triacylglycerol) levels in VLDL from choline-deficient rats, but no change in the levels of phosphatidylcholine, cholesterol, and cholesterol ester in HDL. There were similar levels of apo B and E (components of VLDL) in homogenates of livers from normal and choline-deficient rats, as determined by immunoblotting. These results support the hypothesis that choline deficiency causes reduction of VLDL, but not HDL, levels in plasma as a consequence of impaired hepatic VLDL secretion.
Yao
Z M
ZM
Lipid and Lipoprotein Research Group, University of Alberta, Edmonton, Canada.
Vance
D E
DE
D000818:Animals; D001053:Apolipoproteins / Q000097:blood; D002796:Choline Deficiency / Q000097:blood* / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008075:Lipoproteins, HDL / Q000097:blood*; D008079:Lipoproteins, VLDL / Q000097:blood* / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D001053:Apolipoproteins; D008055:Lipids; D008075:Lipoproteins, HDL; D008079:Lipoproteins, VLDL