Nagaoka S, Masaki H, Aoyama Y, Yoshida A
J Nutr. 1986 May;116(5):726-32. doi: 10.1093/jn/116.5.726.
Comparison of the effects of excess dietary tyrosine, DDT, chlorobutanol (Chloretone) or butylated hydroxyanisole (BHA) on serum cholesterol, hepatic activities of the rate-limiting enzyme of cholesterol synthesis,3-hydroxy-3-methylglutaryl coenzyme A reductase (EC 1.1.1.34) and in vivo rates of the hepatic cholesterol synthesis measured by 3H2O incorporation were investigated in rats. Serum cholesterol concentration was significantly higher in rats fed the DDT, chlorobutanol, BHA or excess tyrosine diets than in rats fed the control diet for 7 days. Serum cholesterol concentration remained higher compared to control rats when excess tyrosine was fed for 21 d. When rats were fed a basal diet after feeding a tyrosine excess diet for 2 wk, liver weight and serum cholesterol level returned to normal within 7 d. The incorporation of 3H2O into liver cholesterol and the activity of liver 3-hydroxy-3-methylglutaryl coenzyme A reductase were greater in rats fed excess tyrosine or certain xenobiotics than in control rats. Present results suggested that the increase in serum cholesterol concentration due to excess dietary tyrosine or certain xenobiotics is mainly attributable to the stimulation of liver cholesterol synthesis.
研究了过量膳食酪氨酸、滴滴涕（DDT）、氯丁醇（三氯叔丁醇）或丁基羟基茴香醚（BHA）对大鼠血清胆固醇、胆固醇合成限速酶——3-羟基-3-甲基戊二酰辅酶A还原酶（EC 1.1.1.34）的肝脏活性以及通过掺入3H2O测定的肝脏胆固醇合成体内速率的影响。喂食DDT、氯丁醇、BHA或过量酪氨酸饮食的大鼠，其血清胆固醇浓度在7天时显著高于喂食对照饮食的大鼠。当过量喂食酪氨酸21天时，与对照大鼠相比，血清胆固醇浓度仍较高。在过量喂食酪氨酸饮食2周后再喂食基础饮食时，大鼠的肝脏重量和血清胆固醇水平在7天内恢复正常。喂食过量酪氨酸或某些外源化学物的大鼠，其肝脏胆固醇中3H2O的掺入量和肝脏3-羟基-3-甲基戊二酰辅酶A还原酶的活性高于对照大鼠。目前的结果表明，过量膳食酪氨酸或某些外源化学物导致的血清胆固醇浓度升高主要归因于肝脏胆固醇合成的刺激。
