title: Carbohydrate type and amount alter intravascular processing and catabolism of plasma lipoproteins in guinea pigs.
abstract: To test the effects of exchanging dietary complex and simple carbohydrate for fat calories on lipoprotein metabolism, guinea pigs were fed two different fat/carbohydrate ratios: 2.5:58% (w/w) or 25:29% (w/w) with either sucrose or starch as the carbohydrate source. Animals fed high-fat had higher plasma low-density lipoprotein (LDL) and hepatic cholesterol concentrations than animals fed low-fat diets (P < 0.01). The cholesteryl ester content per particle was higher, and the number of triacylglycerol (TAG) molecules was lower in very low density lipoprotein (VLDL) and LDL from animals fed high-fat diets. Intake of high-fat/sucrose resulted in higher plasma LDL concentrations than intake of high-fat/starch, and animals fed low-fat/starch had the highest plasma TAG concentrations associated with VLDL particles containing more TAG molecules, as well as a TAG-enriched LDL. The activity of plasma lecithin cholesteryl:acyl transferase (LCAT) was highest in animals fed high-fat/sucrose, and heart lipoprotein lipase (LPL) activity was higher in animals fed high-fat diets. Hepatic apoprotein B/E (apo B/E) receptor number (Bmax) was increased 21% with low-fat diets (P < 0.01). These results suggest that the hypercholesterolemia induced by high-fat and by sucrose intake are associated with a higher plasma LCAT activity which results in a cholesteryl ester-enriched VLDL which, by the action of LPL, might be more readily converted to LDL through the delipidation cascade leading to downregulation of hepatic apo B/E receptors. The hypertriglyceridemia associated with low-fat intake may result from increased production of VLDL TAG, which would explain the increased TAG content and the higher TAG/CE ratio of VLDL from animals fed the low-fat/starch diet.
authors.affiliation: Department of Nutritional Sciences, University of Arizona, Tucson 85721, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Fernandez
authors.forename: A K
authors.initials: AK
authors.lastname: Conde
authors.forename: L R
authors.initials: LR
authors.lastname: Ruiz
authors.forename: C
authors.initials: C
authors.lastname: Montano
authors.forename: J
authors.initials: J
authors.lastname: Ebner
authors.forename: D J
authors.initials: DJ
authors.lastname: McNamara
mesh_terms: D000818:Animals; D001055:Apolipoproteins B / Q000097:blood; D002784:Cholesterol / Q000097:blood; D002788:Cholesterol Esters / Q000097:blood / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004041:Dietary Fats / Q000008:administration & dosage; D002149:Energy Intake; D006168:Guinea Pigs; D008071:Lipoprotein Lipase / Q000378:metabolism; D008074:Lipoproteins / Q000097:blood*; D008077:Lipoproteins, LDL / Q000097:blood; D008079:Lipoproteins, VLDL / Q000097:blood; D008099:Liver / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000201:enzymology; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood; D011973:Receptors, LDL / Q000378:metabolism; D013213:Starch / Q000008:administration & dosage; D013395:Sucrose / Q000008:administration & dosage; D014280:Triglycerides / Q000097:blood
chemical_list: D001055:Apolipoproteins B; D002788:Cholesterol Esters; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D008074:Lipoproteins; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D011973:Receptors, LDL; D014280:Triglycerides; D013395:Sucrose; D013213:Starch; D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase; D008071:Lipoprotein Lipase