title: Prickly pear (Opuntia sp.) pectin reverses low density lipoprotein receptor suppression induced by a hypercholesterolemic diet in guinea pigs.
abstract: The effects of prickly pear pectin on plasma LDL metabolism were investigated by feeding guinea pigs either a diet containing 15 g/100 g lard and 0.25 g/100 g cholesterol (LC diet) or the LC diet in which cellulose was partially replaced (2.5 g/100 g) by prickly pear pectin (LC-P diet). The LC-P diet lowered plasma LDL cholesterol concentrations by 33% (P < 0.001). Low density lipoprotein composition was modified by intake of prickly pear pectin; the relative percentages of free and esterified cholesterol were lower and triglycerides were higher in LDL from animals fed the LC-P diet (P < 0.05). Intake of prickly pear pectin did not affect hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity; however, hepatic free and esterified cholesterol concentrations were lowered by 46 and 64%, respectively. Hepatic apolipoprotein B/E receptor expression (Bmax) was 60% higher in animals fed the LC-P diet (P < 0.01). Similar to the in vitro data, receptor-mediated LDL fractional catabolic rates were 190% higher in animals fed the LC-P diet (P < 0.05), whereas apolipoprotein LDL flux rates were not affected. Apolipoprotein LDL pool size and fractional catabolic rates exhibited a significant correlation (r = -0.52, P < 0.01). These data indicate that an increase in apolipoprotein B/E receptor expression is a major metabolic response by which intake of prickly pear pectin decreases plasma LDL concentrations.
authors.affiliation: Department of Nutrition and Food Science, University of Arizona, Tucson 85721.
authors.forename: M L
authors.initials: ML
authors.lastname: Fernandez
authors.forename: E C
authors.initials: EC
authors.lastname: Lin
authors.forename: A
authors.initials: A
authors.lastname: Trejo
authors.forename: D J
authors.initials: DJ
authors.lastname: McNamara
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D002788:Cholesterol Esters / Q000097:blood / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000008:administration & dosage / Q000494:pharmacology*; D008078:Cholesterol, LDL / Q000097:blood; D006168:Guinea Pigs; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D010368:Pectins / Q000494:pharmacology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D011973:Receptors, LDL / Q000187:drug effects* / Q000378:metabolism; D018110:Receptors, Lipoprotein; D014280:Triglycerides / Q000097:blood
chemical_list: D002788:Cholesterol Esters; D002791:Cholesterol, Dietary; D008078:Cholesterol, LDL; D011956:Receptors, Cell Surface; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; D014280:Triglycerides; C032531:apolipoprotein B,E receptor; D010368:Pectins; D002784:Cholesterol; D006903:Hydroxymethylglutaryl CoA Reductases