title: Regulatory effects of the saturated fatty acids 6:0 through 18:0 on hepatic low density lipoprotein receptor activity in the hamster.
abstract: The plasma concentration of cholesterol carried in low density lipoproteins is principally determined by the level of LDL receptor activity (Jm) and the LDL-cholesterol production rate (Jt) found in animals or man. This study delineates which saturated fatty acids alter Jm and Jt and so increase the plasma LDL-cholesterol level. Jm and Jt were measured in vivo in hamsters fed a constant level of added dietary cholesterol (0.12%) and triacylglycerol (10%), where the triacylglycerol contained only a single saturated fatty acid varying in chain length from 6 to 18 carbon atoms. After feeding for 30 d, the 12:0, 14:0, 16:0, and 18:0 fatty acids, but not the 6:0, 8:0, and 10:0 compounds, became significantly enriched in the liver total lipid fraction of the respective groups fed these fatty acids. However, only the 12:0, 14:0, and 16:0 fatty acids, but not the 6:0, 8:0, 10:0, and 18:0 compounds, suppressed Jm, increased Jt, and essentially doubled plasma LDL-cholesterol concentrations. Neither the 16:0 nor 18:0 compound altered rates of cholesterol synthesis in the extrahepatic organs, and both lowered the hepatic total cholesterol pool. Thus, the different effects of the 16:0 and 18:0 fatty acids could not be attributed to a difference in cholesterol delivery to the liver. Since these changes in LDL kinetics took place without an apparent alteration in external sterol balance, the regulatory effects of the 12:0, 14:0, and 16:0 fatty acids presumably are mediated through some change in a putative intrahepatic regulatory pool of sterol in the liver.
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: L A
authors.initials: LA
authors.lastname: Woollett
authors.forename: D K
authors.initials: DK
authors.lastname: Spady
authors.forename: J M
authors.initials: JM
authors.lastname: Dietschy
mesh_terms: D000818:Animals; D008078:Cholesterol, LDL / Q000378:metabolism; D006224:Cricetinae; D005227:Fatty Acids / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008647:Mesocricetus; D011973:Receptors, LDL / Q000032:analysis*; D014280:Triglycerides / Q000494:pharmacology
chemical_list: D008078:Cholesterol, LDL; D005227:Fatty Acids; D008077:Lipoproteins, LDL; D011973:Receptors, LDL; D014280:Triglycerides