[Plasma selenium concentration, glutathione peroxidase and glutathione S-transferase activities in patients with chronic liver diseases].
The effects exerted on hepatocytes by alcohol metabolites, drugs or other toxins and also hepatotropic viruses lead to chronic liver diseases. Reactive oxygen species (ROS) have been implicated in a number of pathologies, including different types of liver diseases. Organism has developed several mechanisms to counteract or prevent reactive oxygen species effects. These include enzymes such as: glutathione peroxidase (GSH-Px) with selenium (Se) in the active site and glutathione S-transferase (GST). Measurement of GST, compared with alanine aminotransferase (AIAT), has been advocated as a superior marker of hepatocellular damage. The aim of this study was to assess selenium concentration, glutathione peroxidase and glutathione S-transferase activities in plasma of patients with various types of liver diseases. The study population consisted of 54 patients and 25 healthy volunteers. The patients were divided into two groups according to etiology of the disease. Plasma selenium concentration was reduced in patients with cirrhosis, as compared to controls, irrespective of etiology and activity of AIAT. Plasma GSH-Px activity was significantly lower in both groups of patients with normal AIAT activity, whereas it was higher in both groups with activity of AIAT higher than 40 U/l. GST activity was higher only in post-viral group in patients with high AIAT activity. Impaired intestinal absorption and distribution of selenium among plasma proteins have been suggested as possible mechanism of reduced selenium concentration. Changes in the activities of glutatthione-dependent enzymes in plasma may arise from increased formation of reactive oxygen species or from release of these enzymes from injured hepatocytes to plasma.