Murakami Shigeru, Kondo Yukiko, Toda Yoshihisa, Kitajima Hideaki, Kameo Kazuya, Sakono Masanobu, Fukuda Nobuhiro
Medicinal Research Laboratories, Taisho Pharmaceutical Co, Ltd, Saitama, Japan.
Life Sci. 2002 Apr 5;70(20):2355-66. doi: 10.1016/s0024-3205(02)01507-2.
The effects of taurine on hepatic cholesterol metabolism were investigated in hamsters fed a high-fat diet or normal chow. Two weeks-treatment of taurine at 1% in drinking water prevented high-fat diet-induced increase in cholesterol levels of serum and liver. The decrease in serum cholesterol by taurine was due to decrease in non-HDL cholesterols. A similar tendency was noted in serum and liver cholesterol levels of hamsters fed a normal diet. In hamsters fed a high-fat diet, taurine prevented elevation in hepatic activity of acyl-CoA:cholesterol acyltransferase (ACAT) and increased the activity of cholesterol 7alpha-hydroxylase. Taurine also increased cholesterol 7alpha-hydroxylase activity in hamsters fed normal chow. Studies on liver membranes revealed that taurine increased 125I-labeled LDL binding by 52% and 58% in hamsters fed either a normal chow or high-fat diet, respectively. Furthermore, LDL kinetic analysis showed that taurine intake resulted in significant faster plasma LDL fractional catabolic rates (FCR). These results suggest that taurine elevates hepatic LDL receptor and thereby decreases serum cholesterol levels, an event which may be the result of hepatic cholesterol depletion as a consequence of increased bile acid synthesis via enhancement of cholesterol 7alpha-hydroxylase activity. Thus, up-regulation of the LDL receptor and subsequent increase in receptor- mediated LDL turnover may be a key event in the cholesterol-lowering effects of taurine in hamsters.
研究了牛磺酸对高脂饮食或正常饲料喂养的仓鼠肝脏胆固醇代谢的影响。在饮用水中添加1%牛磺酸进行为期两周的处理，可防止高脂饮食诱导的血清和肝脏胆固醇水平升高。牛磺酸降低血清胆固醇是由于非高密度脂蛋白胆固醇降低所致。在喂食正常饮食的仓鼠的血清和肝脏胆固醇水平上也观察到类似趋势。在高脂饮食喂养的仓鼠中，牛磺酸可防止酰基辅酶A：胆固醇酰基转移酶（ACAT）的肝脏活性升高，并增加胆固醇7α-羟化酶的活性。牛磺酸也增加了喂食正常饲料的仓鼠的胆固醇7α-羟化酶活性。对肝细胞膜的研究表明，在喂食正常饲料或高脂饮食的仓鼠中，牛磺酸分别使125I标记的低密度脂蛋白（LDL）结合增加了52%和58%。此外，LDL动力学分析表明，摄入牛磺酸导致血浆LDL分数分解代谢率（FCR）显著加快。这些结果表明，牛磺酸可提高肝脏LDL受体水平，从而降低血清胆固醇水平，这一事件可能是由于胆固醇7α-羟化酶活性增强导致胆汁酸合成增加，进而引起肝脏胆固醇消耗的结果。因此，LDL受体的上调以及随后受体介导的LDL周转率增加可能是牛磺酸降低仓鼠胆固醇作用的关键事件。
