ISSN:
1432-0738
Schlagwort(e):
Key words: Peroxisome proliferators – Rat and monkey hepatocyte cultures – Antioxidant enzyme activities
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract. The effect of hypolipidaemic compounds on peroxisomal fatty acid β-oxidation and on peroxisome morphology in the liver differs widely between rodent and primate species. We studied the relative importance of peroxisomal and mitochondrial β-oxidation of palmitate in primary cultures of hepatocytes isolated from rat and monkey liver in the absence or presence of clofibric acid or beclobric acid. It was demonstrated that it is possible to differentiate between peroxisomal and mitochondrial β-oxidation activities in intact cells. Overall β-oxidation of palmitate was ca. 30% higher in rat hepatocytes than in monkey liver cells. In both monkey and rat cell cultures the mitochondrial component was over 90% of the total palmitate β-oxidation. In rat hepatocyte culture clofibric acid and beclobric acid caused a 5- to 8-fold stimulation of peroxisomal β-oxidation, while in monkey cells this activity was not significantly increased. However, in cells derived from both species mitochondrial palmitate β-oxidation was increased (rat 2.5-fold; monkey 1.5-fold). These results indicate that the species differences in the increase in peroxisomal fatty acid oxidation are not a result of an inability to metabolize fatty acids in rat liver cell mitochondria. A comparison of the activity of enzymes involved in the detoxification of hydrogen peroxide showed that catalase and glutathione-S-transferase activity is 2.9-fold higher in monkey hepatocytes than in rat liver cells, while glutathione peroxidase activity was 1.6-fold higher in rat cells. When a comparison between both species is made for the ratio of hydrogen peroxide production over catalase activity, it can be concluded that this peroxide will have much smaller possibilities to escape from the peroxisomal compartment in monkey hepatocytes. These findings suggest that species differences in these enzyme activities can contribute to differences in susceptibility for peroxisome proliferator-induced carcinogenicity between rodents and primates.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/s002040050103
Permalink
