title: The effect of storage at - 80 degrees C on the activities of cytoplasmic, mitochondrial and microsomal enzymes in rat liver.
abstract: The effect of storage at - 80 degrees C for 1-28 days on the activity of 12 enzymes in intact liver tissue, liver extract and isolated hepatic microsomes was investigated. To find optimal conditions for tissue homogenization for this study the effects of three types of homogenization on the activity of 10 enzymes from different cell compartments were compared. The activities of glucokinase and phosphofructokinase decreased markedly during storage of both supernatant and liver tissue. Storage of liver tissue increased the activity of mitochondrial enzymes or isoenzymes. While this effect can be explained by additional disintegration of liver tissue caused by freezing and thawing for enzymes like glutamine dehydrogenase, other mechanisms may be involved in the prolonged increase observed in the activity of citrate synthase and xanthine oxidase during storage. The activity of a number of enzymes from the cytosol, mitochondria and microsomes decreased more markedly in the stored liver samples than in the stored supernatant or in the stored microsomal pellet. Cytochrome P 450 content remained stable throughout the whole storage period in both intact liver tissue and isolated microsomes.
mesh_terms: D000818:Animals; D003080:Cold Temperature; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis; D003593:Cytoplasm / Q000201:enzymology; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D013048:Specimen Handling; D013997:Time Factors
chemical_list: D003577:Cytochrome P-450 Enzyme System