Mechanisms by which saturated triacylglycerols elevate the plasma low density lipoprotein-cholesterol concentration in hamsters. Differential effects of fatty acid chain length.
These studies were designed to elucidate how shorter (MCT) and longer (HCO) chain-length saturated triacylglycerols and cholesterol interact to alter steady-state plasma LDL-cholesterol levels. When either MCT or HCO was fed in the absence of cholesterol, there was little effect on receptor-dependent LDL transport but a 36-43% increase in LDL-cholesterol production. Cholesterol feeding in the absence of triacylglycerol led to significant suppression of receptor-dependent LDL transport and a 26-31% increase in LDL-cholesterol production. However, when the longer chain-length saturated triacylglycerol was fed together with cholesterol there was a marked increase in the suppression of receptor-dependent LDL transport and an 82% increase in production rate. Together, these two alterations accounted for the observed eightfold increase in plasma LDL-cholesterol concentration. In contrast, feeding the shorter chain-length saturated triacylglycerol with cholesterol actually enhanced receptor-dependent LDL transport while also causing a smaller increase (52%) in the LDL-cholesterol production rate. As a result of these two opposing events, MCT feeding had essentially no net effect on plasma LDL-cholesterol levels beyond that induced by cholesterol feeding alone.
Woollett
L A
LA
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235 8887.
Spady
D K
DK
Dietschy
J M
JM
D000818:Animals; D002784:Cholesterol / Q000096:biosynthesis; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood*; D006224:Cricetinae; D004041:Dietary Fats / Q000494:pharmacology; D005227:Fatty Acids / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D011973:Receptors, LDL / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D005227:Fatty Acids; D011973:Receptors, LDL; D014280:Triglycerides; D002784:Cholesterol