Dietary myristic acid modifies the HDL-cholesterol concentration and liver scavenger receptor BI expression in the hamster.
The influence of myristic acid in a narrow physiological range (0.5 to 2.4% of total dietary energy) on the plasma and hepatic cholesterol metabolism was investigated in the hamster. The hamsters were fed on a diet containing 12.5 g fat/100 g and 0.05 g cholesterol/100 g with 0.5% myristic acid (LA diet) for 3 weeks (pre-period). During the following 3 weeks (test period), they were divided into four dietary groups with 0.5% (LA), 1.2% (LM), 1.8% (ML) or 2.4% (M) myristic acid. Finally, half the hamsters in each group were again fed the LA diet for another 3 weeks (post-period). At the end of the test period, the hepatic expression of the scavenger receptor BI (SR-BI) was lower in the LM, ML and M groups than in the LA group whereas the hepatic cholesteryl ester concentration was higher. Cholesterol 7alpha hydroxylase activity was lower in the ML and M groups than in the LA and LM groups while the sterol 27 hydroxylase and 3-hydroxy-3-methyl glutaryl coenzyme A reductase activities were not modulated by dietary myristic acid. This is the first time a negative correlation has been observed between the HDL-cholesterol concentration and the hepatic mass of SR-BI (r -0.69; P<0.0001) under physiological conditions. An inverse linear regression was also shown between SR-BI and the percentage of myristic acid in the diet (r -0.75; P<0.0001). The hepatic mass of SR-BI in the M group had increased at the end of the post-period compared with the test-period values. The present investigation shows that myristic acid modulates HDL-cholesterol via a regulation of the SR-BI expression.
Loison
Carole
C
Laboratoire de Physiologie de la Nutrition (laboratorie associé à l'INRA), Université Paris-Sud, Centre d'Orsay, France.
Mendy
François
F
Sérougne
Colette
C
Lutton
Claude
C
D000818:Animals; D018955:CD36 Antigens / Q000187:drug effects* / Q000378:metabolism; D053493:Cholestanetriol 26-Monooxygenase; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism; D008076:Cholesterol, HDL / Q000187:drug effects* / Q000378:metabolism; D006224:Cricetinae; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004032:Diet; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D008647:Mesocricetus; D019814:Myristic Acid / Q000494:pharmacology*; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B; D013250:Steroid Hydroxylases / Q000378:metabolism
D018955:CD36 Antigens; D008076:Cholesterol, HDL; D008055:Lipids; D008074:Lipoproteins; D008565:Membrane Proteins; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; C030104:lipoprotein cholesterol; D019814:Myristic Acid; D003577:Cytochrome P-450 Enzyme System; D002784:Cholesterol; D013250:Steroid Hydroxylases; D002790:Cholesterol 7-alpha-Hydroxylase; D053493:Cholestanetriol 26-Monooxygenase; C506832:Cyp27a1 protein, mouse