The effect of the uremic toxin cyanate (CNO−) on anaerobic cysteine metabolism and oxidative processes in the rat liver: a protective effect of lipoate

Chronic renal failure (CRF) patients have an increased plasma level of urea, which can be a source of cyanate. This compound can cause protein carbamoylation thereby changing biological activity of proteins. Therefore, in renal failure patients, cyanate can disturb metabolism and functioning of the liver. This work presents studies demonstrating that the treatment of rats with cyanate alone causes the following changes in the liver: (1) inhibition of rhodanese (TST), cystathionase (CST) and 3-mercaptopyruvate sulfotransferase (MPST) activities, (2) decrease in sulfane sulfur level (S*), (3) lowering of nonprotein sulfhydryl groups (NPSH) group level, and (4) enhancement of prooxidant processes (rise in reactive oxygen species (ROS) and malondialdehyde (MDA) level). This indicates that cyanate inhibits anaerobic cysteine metabolism and shows prooxidant action in the liver. Out of the above-mentioned changes, lipoate administered with cyanate jointly was able to correct MDA, ROS and NPSH levels, and TST act...