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.
Departamento de Fisiologiía Animal, Facultad de Farmacia, Sevilla, Spain.
M T
MT
Molina
C M
CM
Vázquez
V
V
Ruiz-Gutierrez
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