Phospholipid Composition of Liver Homogenates and Microsomes of the Lean and Obese Hyperglycemic (OB/OB) Mouse

Varandani, Partab T.; Darrow, Ruth M.; Nafz, Mary Ann

doi:10.3181/00379727-156-39889

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…The protein content was estimated by the method of Lowry et al [13] with bovine serum albumin as standard. Mem brane phospholipids were extracted by the method of Folch et al [5] and separated by bidimensional thin layer chromatography [26]. After iodine exposure, each phospholipid was scraped off and determined by phosphorus assay using the method of Chen et al [3].…”

Section: Methodsmentioning

confidence: 99%

Phenobarbital Induction of Cytochrome P-450 and UDPGlucuronosyltransferase in Rabbit Liver Plasma Membranes

Magdalou

Antoine

Ratanasavanh

et al. 1982

Enzyme

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The presence of cytochrome P-450 and UDP-glucuronosyltransferase was confirmed in rabbit liver plasma membranes. Their levels, expressed as amount or activity/mg protein, were 25 and 40% respectively of those found in hepatic microsomes. Both enzymes were induced by phénobarbital treatment of the animals: administration of the barbiturate for 4 days, produced a 150% increase in the cytochrome P-450 content and in the specific activity of UDP-glucuronosyltransferase. As compared with the microsomal enzymes, the plasma membrane enzymes were localized in a lipid environment characterized by high levels of cholesterol and sphingomyelin and a low level of phosphatidylcholine. Treatment with phénobarbital for 4 days also caused a significant increase of phosphatidylcholine and phosphatidylethanolamine content in plasma membranes.

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Section: Methodsmentioning

confidence: 99%

Phenobarbital Induction of Cytochrome P-450 and UDPGlucuronosyltransferase in Rabbit Liver Plasma Membranes

Magdalou

Antoine

Ratanasavanh

et al. 1982

Enzyme

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“…In the rat liver, the enzyme occurs bound to membranes as a phospholipoprotein complex in latent and nonlatent (active) forms ( [20]. There is evidence that the proportions of the two forms are different under different pathological and physiological conditions [16,30] and that the degree of latency may be related to the nature of the phosphotipid composition of the membrane [26]. The enzyme contains multiple sites of reaction [28] and, as discussed previously [25], the interactions in situ of different reaction sites with mere-0012-186X/81/0021/0464/$01.20 Streptozotocin-diabetic rat pancreas.…”

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confidence: 99%

“…Compared with the lean mouse pancreas, GIT immunoreactivity is increased both in acinar cells and islets, although it is much more enhanced in the islets. 200 x brane components (such as phospholipids [26,28]) provide different compartments and micro-environments, thereby resulting in selectivity and different local effective enzyme activities.…”

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confidence: 99%

Insulin degradation. XXVIII. Immunocytochemical localization of glutathione-insulin transhydrogenase in the pancreas, kidney and liver of normal and streptozotocin-diabetic rats and of lean and obese (ob/ob) mice

Taylor

Varandani

1981

Diabetologia

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Glutathione-insulin transhydrogenase catalyzed the inactivation of insulin by splitting the hormone into A and B chains. We have localized this enzyme immunocytochemically by light microscopy in the pancreas, kidney and liver of both lean and obese (ob/ob) mice and similarly in normal and streptozotocin-diabetic rats. Localization was achieved by an antibody to glutathione-insulin transhydrogenase using a peroxidase-antiperoxidase technique. In comparison with tissues from control animals, positive immunostaining for glutathione-insulin transhydrogenase was increased in the obese mouse but reduced in the diabetic rat. Different tissues showed considerable variation in the amount of glutathione-insulin transhydrogenase which could be detected. In the pancreatic islets there was little or no evidence for the presence of the enzyme in peripheral cells. In the kidney, immunocytochemical staining was found only in the proximal tubules. In the liver there was a generalised distribution of the enzyme, but the greatest concentration was in the periportal region. These observations parallel the biochemical data relating to glutathione-insulin transhydrogenase, indicating that different amount of insulin degrading activity exist in different regions of tissues.

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Studies on the Control of Lipogenesis: Strain Differences in Hepatic Metabolism

Berdanier

Tobin

DeVore

1979

The Journal of Nutrition

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Detailed studies of hepatic metabolism of lipemic BHE and nonlipemic Wistar rats were conducted. Hepatic lipogenic capacity was varied through the use of starvation or meal feeding. Livers were clamped in precooled copper plates and used for the assay of glycolytic, gluconeogenic, and lipogenic metabolites. Redox and phosphorylation states were calculated. Mitochondrial metabolism was evaluated through studies of the oxygen consumption of isolated mitochondria and through the study of the activities of the alpha-glycerophosphate and malate aspartate shuttles and ATPase. BHE rats have higher phosphorylation states, higher redox ratios, and lower shuttle activities and oxygen consumption by isolated mitochondria than their Wistar cohorts. The differences in oxidative phosphorylation, redox and phosphorylation states, and in the various shuttle activities suggest that BHE liver cells are geared towards lipogenesis at the expense of oxidative phosphorylation. It appears that the activity of the shuttles is controlled in part by phosphorylation state which in turn appears to affect respiration. We theorize from these data that genetically determined differences in the structure and function of the mitochondrial membrane (and perhaps the cell membrane as well) may affect the communication (via metabolites and adenine nucleotides) between the cytosol and mitochondria. Subtle differences in the exchange of metabolites and/or adenine nucleotides across the mitochondrial membrane could thus explain the lipogenic tendency of the liver of the BHE rat and the subsequent development of maturity onset hyperlipemia and hyperglycemia in this strain of rat.

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Phospholipid Composition of Liver Homogenates and Microsomes of the Lean and Obese Hyperglycemic (OB/OB) Mouse

Cited by 3 publications

References 7 publications

Phenobarbital Induction of Cytochrome P-450 and UDPGlucuronosyltransferase in Rabbit Liver Plasma Membranes

Phenobarbital Induction of Cytochrome P-450 and UDPGlucuronosyltransferase in Rabbit Liver Plasma Membranes

Insulin degradation. XXVIII. Immunocytochemical localization of glutathione-insulin transhydrogenase in the pancreas, kidney and liver of normal and streptozotocin-diabetic rats and of lean and obese (ob/ob) mice

Studies on the Control of Lipogenesis: Strain Differences in Hepatic Metabolism

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