[Effects of high-carbohydrate diet on VLDL-, HDL-, and apolipoprotein CII-receptor activities on liver parenchymal and non-parenchymal cells in rats].
We studied the functions of hepatic VLDL-, HDL-, and apolipoprotein (apo) CIII-receptors in the endogenous hypertriglyceridemic (HTG) rats induced by feeding a high-carbohydrate diet (HCD) (80% of total calories). Compared with the control rats (60% of total calories in CHO), the fasting plasma triglyceride (TG) levels of the rats fed on the CHO diet for 5 days increased by 113.4% (P < 0.025, n = 6), but HDL-C and total cholesterol concentrations decreased by 28.4% and 14.4% (P < 0.05, P < 0.05). The binding (Bmax) and uptake of 125I-labeled VLDL by liver non-parenchymal cells (NPC) from HTG rats decreased by 65.0% and 19.1% (P < 0.001, P > 0.05) respectively. The binding of 125I-labeled apoE-deficient HDL3 to the NPC also decreased significantly (-54.5%, P < 0.05). But the affinities (Ka) of the two receptors were prone to increasing. However, the activities of VLDL- and HDL-receptors on liver parenchymal cells didn't significantly change. Meanwhile, the specific binding of 125I-labeled apo CIII to NPC from HTG rats increased by 104.5% (P < 0.025). The results of this study suggest that hepatic VLDL- and HDL-receptors could be down- and up-regulated respectively in response to plasma lipoprotein concentrations in the high CHO dietary rats, and apo CIII-receptor might play an important role in regulating VLDL- and HDL-receptor activities.
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D000818:Animals; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C / Q000378:metabolism*; D002352:Carrier Proteins; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D015228:Hypertriglyceridemia / Q000209:etiology / Q000378:metabolism; D008075:Lipoproteins, HDL; D008099:Liver / Q000378:metabolism*; D008297:Male; D016601:RNA-Binding Proteins; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism*; D018110:Receptors, Lipoprotein / Q000378:metabolism*
D053304:Apolipoprotein C-II; D001056:Apolipoproteins C; D002352:Carrier Proteins; D004040:Dietary Carbohydrates; D008075:Lipoproteins, HDL; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; C036053:VLDL receptor; C031616:high density lipoprotein receptors; C075197:high density lipoprotein binding protein