Changes in both acyl-CoA:cholesterol acyltransferase activity and microsomal lipid composition in rat liver induced by distal-small-bowel resection.
The acyl-CoA:cholesterol acyltransferase (ACAT) activity and lipid composition of hepatic microsomal membrane were investigated 6 weeks after both 50 and 75% distal-small-bowel resection (SBR). A significant decrease in hepatic cholesteryl ester levels was observed after SBR, with a significant increase in the cholesteryl ester content of the livers of 75% SBR compared with the 50% SBR. Hepatic total acylglycerols, free cholesterol and phospholipid levels were not modified after the surgical operation. Microsomal free cholesterol was increased after both 50 and 75% SBR. However, a decrease in both microsomal ACAT activity and cholesteryl ester levels were found in microsomes (microsomal fractions) of resected rats, both changes being higher after 75 than after 50% resection. The total phospholipid content of the microsomes did not change after the surgical operation. The microsomal phospholipid fatty acid composition indicated higher changes after 75 than after 50% SBR. These results demonstrated that, in resected animals: (1) the activity of the enzyme responsible for catalysing cholesterol esterification (ACAT) is decreased, and (2) hepatic microsomal free cholesterol does not appear to influence the activity of ACAT.
Molina
M T
MT
Departamento de Fisiologiía Animal, Facultad de Farmacia, Sevilla, Spain.
Vázquez
C M
CM
Ruiz-Gutierrez
V
V
D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D007421:Intestine, Small / Q000502:physiology*; D050356:Lipid Metabolism; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D002785:Sterol O-Acyltransferase / Q000378:metabolism*; D014280:Triglycerides / Q000378:metabolism
D002788:Cholesterol Esters; D005227:Fatty Acids; D010743:Phospholipids; D014280:Triglycerides; D002784:Cholesterol; D002785:Sterol O-Acyltransferase