Biomaterial Database

Effect of gemfibrozil on centrifugal behavior of rat peroxisomes and activities of peroxisomal enzymes involved in lipid metabolism. 1997

F Hashimoto, and S Hamada, and H Hayashi

Faculty of Pharmaceutical Sciences, Josai University, Saitama, Japan.

The effect of gemfibrozil, and analogue of clofibric acid, on the centrifugal behavior of peroxisomes and activity of peroxisomal enzymes involved in lipid metabolism was studied. Rats were fed chow containing 0.2% gemfibrozil for 2 weeks. Nycodenz gradient centrifugation of the light mitochondrial fraction revealed that peroxisomes of gemfibrozil-treated rats were concentrated in fractions of higher density compared with control rats. The activity of fatty acyl-CoA oxidase, crotonase, beta-hydroxybutyryl-CoA dehydrogenase, and thiolase (individual enzymes of the peroxisomal fatty acid beta-oxidation system) were enhanced 9.6, 2.3, 3.4 and 9.1 times respectively compared with controls, by treatment. The hydroxymethylglutaryl-CoA (HMG-CoA) reductase (rate-limiting enzyme of cholesterol synthesis) activity of peroxisomes and microsomes was greatly increased by in vivo treatment with gemfibrozil, but was decreased by addition of the agent to the assay mixture of the enzyme. Gemfibrozil directly inhibited the reductase activity and did so at a lower concentration than clofibric acid. Peroxisomal reductase was more resistant to damage by the agent than the microsomal enzyme. The HMG-CoA reductase activity of peroxisomes and microsomes of hyperlipidemic rats was also increased by in vivo treatment with gemfibrozil, whereas the serum cholesterol level was hardly changed. These results indicate that the effect of gemfibrozil differs from that of clofibric acid, the main difference being the effect on HMG-CoA reductase. Gemfibrozil increased reductase activity in vivo, unlike clofibric acid, but inhibited the enzyme in vitro to a greater extent than clofibric acid.

UI	MeSH Term	Description	Entries
D008055	Lipids	A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)	Lipid
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008297	Male		Males
D008830	Microbodies	Electron-dense cytoplasmic particles bounded by a single membrane, such as PEROXISOMES; GLYOXYSOMES; and glycosomes.	Glycosomes,Glycosome,Microbody
D008862	Microsomes, Liver	Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.	Liver Microsomes,Liver Microsome,Microsome, Liver
D008930	Mitochondria, Liver	Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)	Liver Mitochondria,Liver Mitochondrion,Mitochondrion, Liver
D002458	Cell Fractionation	Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.	Cell Fractionations,Fractionation, Cell,Fractionations, Cell
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D005227	Fatty Acids	Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)	Aliphatic Acid,Esterified Fatty Acid,Fatty Acid,Fatty Acids, Esterified,Fatty Acids, Saturated,Saturated Fatty Acid,Aliphatic Acids,Acid, Aliphatic,Acid, Esterified Fatty,Acid, Saturated Fatty,Esterified Fatty Acids,Fatty Acid, Esterified,Fatty Acid, Saturated,Saturated Fatty Acids
D006903	Hydroxymethylglutaryl CoA Reductases	Enzymes that catalyze the reversible reduction of alpha-carboxyl group of 3-hydroxy-3-methylglutaryl-coenzyme A to yield MEVALONIC ACID.	HMG CoA Reductases,3-Hydroxy-3-methylglutaryl CoA Reductase,HMG CoA Reductase,Hydroxymethylglutaryl CoA Reductase,3 Hydroxy 3 methylglutaryl CoA Reductase,CoA Reductase, 3-Hydroxy-3-methylglutaryl,Reductase, 3-Hydroxy-3-methylglutaryl CoA