1. Sigma (sigma) receptors have generated a great deal of interest on the basis of their possible roles in various pathologies, including cytoprotection. Although the exact function of sigma-1 (sigma(1)) receptors is not yet known, their role in the regulation of intracellular Ca(2+) levels and sterol biosynthesis, functions that could be assigned to mitochondria, are the only mechanisms descri...

The distribution of marker enzymes in subcellular frac tions isolated by differential centrifugation was determined in Morris hepatoma 16, host liver, and control rat liver. Marker enzymes of cellular organdÃ-esthat were assayed in cluded cytochrome oxidase, monoamine oxidase, ornithine aminotransferase, D-amino acid oxidase, acid phosphatase, glucose 6-phosphatase, ethylmorphine demethylase, a...

1. Liver carnitine acyltransferase activities with palmitoyl-CoA and octanoyl-CoA as substrates and heart carnitine palmitoyltransferase were measured as overt activities in whole mitochondria or in mitochondria disrupted by sonication or detergent treatment. All measurements were made in sucrose/KCl-based media of 300 mosmol/litre. 2. In liver mitochondria, acyltransferase measured with octano...

An increased mitochondrial proton leak occurs in aging, but the origin of such modification remains unclear. This study defined the cause of mitochondrial uncoupling in mitotic (liver) and postmitotic (heart) rat tissues during aging and its effects on energy homeostasis and free radical production. Proton leak in old heart mitochondria was dependent on uncoupling proteins' upregulation, wherea...

1. A continuously recording and sensitive fluorimetric assay is described for carnitine palmitoyltransferase. This assay has been applied to whole or disintegrated mitochondria and to soluble protein fractions. 2. When rat liver mitochondria had been disintegrated by ultrasound, the specific activity of carnitine palmitoyltransferase was 15-20m-units/mg of protein. Only one-fifth of this activi...

The distribution of marker enzymes in subcellular frac tions isolated by differential centrifugation was determined in Morris hepatoma 16, host liver, and control rat liver. Marker enzymes of cellular organdÃ-esthat were assayed in cluded cytochrome oxidase, monoamine oxidase, ornithine aminotransferase, D-amino acid oxidase, acid phosphatase, glucose 6-phosphatase, ethylmorphine demethylase, a...

The enzymes of prolinsglutamate oxidation and the preparation of their substrates have been described by Strecker and coworkers. [ 1,3] . The presence of proline oxidase in rat liver mitochondria was described by Johnson and Strecker [2]. A rough localisation of proline oxidase and A-pyrroline&carboxylic acid dehydrogenase in locust flight muscle has been attempted by Brosemer and Veerabhadrapp...

Reproduction is thought to come at a cost to longevity. Based on the assumption that increased energy expenditure during reproduction is associated with increased free-radical production by mitochondria, oxidative damage has been suggested to drive this trade-off. We examined the impact of reproduction on liver mitochondrial function by utilizing post-reproductive and non-reproductive house mic...

Saponin permeabilization of tissue slices is increasingly popular for characterizing mitochondrial function largely because it is fast, easy, requires little tissue and leaves much of the cell intact. This technique is well described for mammalian muscle and brain, but not for liver. We sought to evaluate how saponin permeabilization reflects aspects of liverenergymetabolism typicallyassessed i...

The early effect of the administration of hydrocortisone on the liver parenchymal cell and thymus lymphocyte was followed chronologically with respect to (a) the contents of nucleic acid and protein and (b) the ultrastructural integrity of the subcellular components. In the electron microscopic study, morphometric and stereographic techniques combined with statistical analysis were applied for ...