Intranuclear distribution, function and fate of glutathione and glutathione-S-conjugate in living rat hepatocytes studied by fluorescence microscopy

Abstract

The availability of fluorescent probes to detect soluble and protein- bound thiols has made it possible to investigate some aspects of reduced glutathione (GSH) metabolism and function in intact rat hepatocytes and in hepatocyte nuclei. Monochlorobimane (BmCl) has been employed to study the subcellular compartmentation of GSH and the formation and fate of the BmCl- GSH conjugate. The occurrence of relatively high concentrations of GSH within the nuclear matrix has been inferred from fluorescence quantitation using image analysis. Concomitant biochemical studies have revealed the presence of a GSH-stimulated ATP hydrolysis and of an ATP-stimulated GSH accumulation in isolated nuclei, providing the molecular basis for nuclear glutathione compartmentation. The contemporary use of fluorescent probes to label nuclear free sulfhydryl groups, proteins and chromatin status led to the demonstration that intranuclear accumulation of glutathione may modulate the thiol/disulfide redox status of nuclear proteins and control chromatin compacting and decondensation.