Metabolic changes in hepatic cholesterol metabolism by dietary amino acid

为了阐明高胱氨酸饲料引起高胆固醇血症的机制，测定了肝脏HMG-CoA还原酶、肝脏HMG-CoA还原酶mRNA、LDL受体mRNA<125>和注射入血的~（131）I-LDL的消失率。结果表明：1.高胱氨酸饲料喂养3-5天后，血清胆固醇升高; 2.高胱氨酸饲料喂养3天后，肝脏HMG-CoA还原酶活性升高; 3.肝脏HMG-CoA还原酶mRNA水平升高1.6- 1.8倍，肝脏HMG-CoA还原酶mRNA水平升高1.6- 1.8倍。高胱氨酸饲料喂养2d后，肝脏LDL受体mRNA表达增加，肝脏LDL受体mRNA从<125>上述结果推测，高胱氨酸饮食引起的高胆固醇血症可能是由于肝脏中胆固醇合成增加所致。

In order to clarify the mechanism for the hypercholesterolemia induced by feeding the cystine rich diet, liver HMG-CoA reductase, liver HMG-CoA reductase mRNA,LDL receptor mRNA and, the disappearance rate of ^<125>I-LDL injected into blood were estimated. The following were found.1.Serum cholesterol was increased within 3-5 days after feeding the cystine rich diet.2.Hepatic HMG-CoA reductase activity was increased within 3 days after feeding the cystine rich diet diet.3.Hepatic HMG-CoA reductase mRNA was increased 1.6-1.8 folds after feeding the cystine rich diet for 2 days.4.LDL receptor mRNA in the liver was increased after feeding the cystine rich diet for 3 days.5.The disappearance rate from the blood of ^<125>I-LDL injected into blood was increased in the rats fed the cystine rich diet.From these results described above, it is surmised that the hypercholesterolemia induced by feeding teh cystin rich diet might be due to the enhanced synthesis of cholesterol in the liver.