Effects of SH-blocking compounds on the energy metabolism in isolated rat hepatocytes

To investigate the importance of SH-groups in the energy metabolism of liver cells, isolated rat hepatocytes were exposed to various SH-blocking compounds. After 1.0 hr exposure, the cells were analyzed for the content of glycogen, lactate, pyruvate, ATP and the rate of oxygen consumption. Without affecting the cell viability, PCMB, PCMBS, mersalyl, NEM, DTP and DSF were found to decrease glycogen levels, whereas the disulphide reagent CDPS did not affect this endogenous energy reserve. Lactate and pyruvate levels were decreased by the organic mercury compounds, whereas NEM, DTP and DSF stimulated the formation of lactate, without affecting the levels of pyruvate. In both situations the oxygen consumption was slightly decreased. The FCCP uncoupled oxygen consumption was not affected. Up to the point of loss of cell viability, as measured by trypan blue exclusion and LDH-leakage, the liver cells maintained their ATP levels, during exposure to the various SH-reagents. In conclusion, the results with organic mercury compounds suggest a reaction of these agents with SH-groups in the outer membrane of cells, having an inhibiting effect on the glucose uptake. The most prominent effect of DTP, DSF and NEM was an increased lactate formation, implying an intracellular effect, most probably in the TCA-cycle.