title: Effect of high levels of selected dietary essential amino acids on hypercholesterolemia and down-regulation of hepatic LDL receptors in rabbits.
abstract: Earlier studies showed that the elevation of serum total and low density lipoprotein (LDL) cholesterol levels produced in rabbits by feeding high levels of a casein amino acid mixture in a cholesterol-free, semipurified diet was due primarily to the essential amino acids (EAA) in the mixture. Replacing all of the non-essential amino acids in the mixture by glutamic acid (45% EAA+Glu) had little effect on the hypercholesterolemia produced by the EAA. Experiments designed to identify the hypercholesterolemic EAA showed that (i) feeding high levels of ketogenic EAA only (45% EketoAA) gave a substantial but variable elevation of serum total and LDL cholesterol and (ii) feeding high levels of all EAA except arginine (45% EAA-Arg) gave a particularly strong hypercholesterolemic response. In rabbits fed the 45% EAA-Arg diet and to a lesser extent, in those fed the 45% EAA+Glu diet, EDTA-sensitive binding of 125I-LDL to hepatic membranes in vitro was reduced compared to a control, low-cholesterolemic group fed all essential and non-essential amino acids at a level corresponding to 14.7% casein, indicating that the hypercholesterolemia was associated with down-regulation of hepatic LDL receptors.
authors.affiliation: Department of Biochemistry, University of Western Ontario, London, Canada.
authors.forename: E M
authors.initials: EM
authors.lastname: Kurowska
authors.forename: K K
authors.initials: KK
authors.lastname: Carroll
mesh_terms: D000601:Amino Acids, Essential / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004032:Diet; D015536:Down-Regulation; D004492:Edetic Acid; D006903:Hydroxymethylglutaryl CoA Reductases / Q000378:metabolism; D006937:Hypercholesterolemia / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D011973:Receptors, LDL / Q000378:metabolism*
chemical_list: D000601:Amino Acids, Essential; D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL; D011973:Receptors, LDL; D004492:Edetic Acid; D006903:Hydroxymethylglutaryl CoA Reductases