Iglesias J, Gonzalez-Pacanowska D, Marco C, Garcia-Peregrin E
Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Granada, Spain.
Lipids. 1993 Jun;28(6):549-53. doi: 10.1007/BF02536087.
The purpose of the present study was to investigate the physiological control of the main regulatory enzymes of cholesterol metabolism in isolated enterocytes obtained from chick duodenum, jejunum and ileum. Cholesterol feeding resulted in an inhibition of 3-hydroxy-3-methyl-glutaryl-CoA reductase and mevalonate 5-pyrophosphate decarboxylase, while cholestyramine feeding increased reductase activity in all the regions studied and decarboxylase activity only in duodenum. Cholesterol feeding markedly increased acyl-CoA:cholesterol acyltransferase, but the effects of cholestyramine were less clear. The effects on transferase activity cannot be due to differences in the availability of acyl-CoA as exogenous substrate as no significant differences were found in acyl-CoA hydrolase activity after any of the dietary treatments. The effects of cholesterol feeding were related to changes in the cholesterol content of epithelial cells, whereas in the case of cholestyramine this relationship was less apparent.
本研究的目的是调查从鸡十二指肠、空肠和回肠分离出的肠细胞中胆固醇代谢主要调节酶的生理控制。喂食胆固醇会抑制3-羟基-3-甲基戊二酰辅酶A还原酶和甲羟戊酸5-焦磷酸脱羧酶，而喂食消胆胺会增加所有研究区域的还原酶活性，且仅增加十二指肠中的脱羧酶活性。喂食胆固醇会显著增加酰基辅酶A：胆固醇酰基转移酶，但消胆胺的作用不太明确。对转移酶活性的影响并非由于酰基辅酶A作为外源性底物的可用性差异，因为在任何饮食处理后，酰基辅酶A水解酶活性均未发现显著差异。喂食胆固醇的影响与上皮细胞胆固醇含量的变化有关，而在消胆胺的情况下，这种关系不太明显。
