Poster Topical Area: Energy and Macronutrient Metabolism
Location: Hall D
Poster Board Number: 498
● Objectives: The purpose of the study was to determine the hypocholesterolemic mechanism of α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) individually with 17β-estradiol-3-benzoate (E) in ovariectomized (OVX) rats.
Methods: Female rats were given one of 4 diets containing 0% n-3 polyunsaturated fatty acids, 1% ALA, 1% EPA or 1% DHA from total energy intake for 12 weeks. At week 8, rats were sham-operated or ovariectomized, and during the last 3 weeks of experimental period, ovariectomized rats were injected with corn oil vehicle or E every 4 days to mimic the menstrual cycle.
Results: Rats fed EPA or DHA with E showed a significant decrease in serum levels of triglyceride, LDL-cholesterol, and increase in serum levels of HDL-cholesterol. Supplementation of EPA or DHA significantly increased the expression of phosphorylated adenosine monophosphate activated protein kinase (p-AMPK)/AMPK ratio, cholesterol 7α-hydroxylase (CYP7A1), sterol 12α-hydroxylase (CYP8B1) and sterol 27-hydroxylase (CYP27A1), and decreased the expressions of 3-hydroxy-3-methylglutaryl coenzyme A reductase, sterol regulatory element-binding protein-2 and proprotein convertase subtilisin/kexin type 9 in liver. However, E significantly decreased the hepatic expressions of CYP7A1 and CYP8B1. In addition, E significantly increased the hepatic expressions of estrogen receptor-α and β. Supplementation of ALA had no significant hypocholesterolemic effect and did not changed the hepatic protein expression related with cholesterol synthesis and clearance.
Conclusions: The present study showed that hypocholesterolemic effect of EPA or DHA was derived from increased hepatic bile acid synthesis, upregulated LDL-receptor, and decreased hepatic cholesterol synthesis. However, hypocholesterolemic effect of E was derived from decreased hepatic cholesterol synthesis and upregulated LDL-receptor, but not by the decreased hepatic bile acid synthesis.
Seongdong-gu, Seoul, Seoul-t'ukpyolsi, Republic of Korea