Nagata J, Oku H, Toda T, Chinen I
Laboratory of Applied Biochemistry, Faculty of Agriculture, School of Medicine, University of the Ryukyus, Okinawa, Japan.
J Nutr Sci Vitaminol (Tokyo). 1996 Aug;42(4):287-300. doi: 10.3177/jnsv.42.287.
The hyperlipidemia- and atherosclerosis-prone (HAP) Japanese quail is a strain developed for the study of atherosclerosis by genetic selection from the commercially available (CA) Japanese quail. To delineate the characteristics of cholesterol metabolism in this strain, concentrations of serum lipids as well as hepatic enzyme activities were compared between HAP and CA quail. The hepatic enzymes studied are involved in the key step reaction in cholesterol metabolism: HMG-CoA reductase, ACAT, and cholesterol 7 alpha-hydroxylase. The animals were fed ad libitum with either 1% cholesterol or cholesterol-free semipurified diet for 28 days. Although a significant increase (p < 0.01) in serum cholesterol was observed in both strains on elapse of cholesterol feeding, formation of atheroma was seen exclusively in HAP quail of the cholesterol-fed group. The serum and liver cholesterol levels of HAP quail fed the cholesterol diet were significantly higher (p < 0.01) than those of CA quail. No significant differences were seen in the rate of cholesterol biosynthesis (HMG-CoA reductase activity), cholesterol ester formation (ACAT activity) and cholesterol catabolism (7 alpha-hydroxylase activity) between CA and HAP quail. Furthermore, the fecal excretions of acidic and neutral sterol showed no significant difference between strains. Although the formation of atheroma in HAP quail may be presumably due to the contribution of the marked increase in serum cholesterol level, the rate of cholesterol catabolism and synthesis in HAP quail compared well with those of CA quail. These observations suggest that the retarded rate of cholesterol biosynthesis or catabolism is not responsible for hypercholesterolemia in HAP quail.
高脂血症和动脉粥样硬化易发性（HAP）日本鹌鹑是通过从市售（CA）日本鹌鹑中进行基因选择而培育出的用于动脉粥样硬化研究的品系。为了描述该品系中胆固醇代谢的特征，比较了HAP和CA鹌鹑的血脂浓度以及肝酶活性。所研究的肝酶参与胆固醇代谢的关键步骤反应：HMG-CoA还原酶、ACAT和胆固醇7α-羟化酶。给动物随意喂食含1%胆固醇或不含胆固醇的半纯化日粮，持续28天。尽管在喂食胆固醇后，两个品系的血清胆固醇均显著升高（p<0.01），但动脉粥样硬化仅在喂食胆固醇组的HAP鹌鹑中出现。喂食胆固醇日粮的HAP鹌鹑的血清和肝脏胆固醇水平显著高于CA鹌鹑（p<0.01）。CA和HAP鹌鹑之间在胆固醇生物合成速率（HMG-CoA还原酶活性）、胆固醇酯形成（ACAT活性）和胆固醇分解代谢（7α-羟化酶活性）方面没有显著差异。此外，两个品系之间酸性和中性固醇的粪便排泄没有显著差异。尽管HAP鹌鹑中动脉粥样硬化的形成可能推测是由于血清胆固醇水平显著升高所致，但HAP鹌鹑的胆固醇分解代谢和合成速率与CA鹌鹑相当。这些观察结果表明，胆固醇生物合成或分解代谢速率的延迟与HAP鹌鹑的高胆固醇血症无关。
