Rosella Fulceri

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The redox state of the intraluminal pyridine nucleotide pool was investigated in rat liver microsomal vesicles. The vesicles showed cortisone reductase activity in the absence of added reductants, which was dependent on the integrity of the membrane. The intraluminal pyridine nucleotide pool could be oxidized by the addition of cortisone or metyrapone but(More)
The functional coupling of 11beta-hydroxysteroid dehydrogenase type 1 and hexose-6-phosphate dehydrogenase was investigated in rat liver microsomal vesicles. The activity of both enzymes was latent in intact vesicles, indicating the intraluminal localization of their active sites. Glucose-6-phosphate, a substrate for hexose-6-phosphate dehydrogenase,(More)
Hexose-6-phosphate dehydrogenase (H6PD) is a luminal enzyme of the endoplasmic reticulum that is distinguished from cytosolic glucose-6-phosphate dehydrogenase by several features. H6PD converts glucose-6-phosphate and NADP(+) to 6-phosphogluconate and NADPH, thereby catalyzing the first two reactions of the pentose-phosphate pathway. Because the(More)
The effects of a number of metabolic inhibitors on the influx of Ca2+ activated by stimulation of receptors coupled to inositol 1,4,5-trisphosphate generation or by depletion of intracellular Ca2+ stores with thapsigargin were investigated in four different cell types: Ehrlich ascites tumor cells, Jurkat and HeLa cell lines, and rat hepatocytes.(More)
Isolated rat hepatocytes treated with mitochondrial inhibitors FCCP or antimycin A release discrete amounts of Ca2+ in a Ca(2+)-free extracellular medium as revealed by changes in the absorbance of the Ca2+ indicator arsenazo III. The process is completed in 2 min and the amount of Ca2+ released is not affected by the type of the mitochondrial poison(More)
During the NADPH-Fe-induced peroxidation of liver microsomal lipids products are formed which are provided with cytopathological activities. In a previous study one of the major products was identified as an aldehyde of the 4-hydroxyalkenal class, namely 4-hydroxynonenal. In the present study another cytotoxic product has been isolated and identified as(More)
A bi-directional, saturable transport of glutathione (GSH) was found in rat liver microsomal vesicles. GSH transport could be inhibited by the anion transport blockers flufenamic acid and 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid. A part of GSH taken up by the vesicles was metabolized to glutathione disulfide (GSSG) in the lumen. Microsomal membrane(More)
Steady-state levels of calcium ions in endoplasmic reticulum reflect a balance between active inward transport, mediated by MgATP-dependent Ca(2+) pumps, and passive backflux of the ions, through putative "leak channels". We have investigated the efflux of Ca(2+) from rat liver microsomal vesicles, passively pre-equilibrated in the presence radiolabelled(More)
11beta-hydroxysteroid dehydrogenase type 1, expressed mainly in the endoplasmic reticulum of adipocytes and hepatocytes, plays an important role in the prereceptorial activation of glucocorticoids. In liver endoplasmic reticulum-derived microsomal vesicles, nicotinamide adenine dinucleotide phosphate reduced supply to the enzyme is guaranteed by a tight(More)
Caffeine mobilized an intracellular Ca2+ pool in intact fura-2-loaded INS-1 cells in suspension exposed to high (16 mM) [glucose], while a minor effect was observed with low (2 mM) [glucose]. Cells were kept in a medium containing diaxozide or no Ca2+ to prevent the influx of extracellular Ca2+. The caffeine-sensitive intracellular Ca2+ pool was within the(More)