Viability, glycolytic capacity and energy metabolism under anaerobic conditions were studied in the hepatoma cell lines HTC, FU5 and HepG2 and in rat and human hepatocytes using glucose and fructose as glycolytic precursors. During 6 hr of anaerobic incubation without additional substrate, viability decreased rapidly in FU5 and HTC cells, whereas viability of HepG2 cells was not significantly affected. In all tumor cells, 10 mmol/L glucose prevented hypoxic cell injury almost completely. Lactate formation from glucose was about five times higher than in hepatocytes under these circumstances. ATP content of the tumor cells remained almost constant under anaerobic conditions in the presence of glucose. Ten millimoles per liter of fructose diminished glycolysis in the hepatoma cells compared with glucose, ranging from 87% reduction in HTC cells to 43% reduction in HepG2 cells. Accordingly, ATP content decreased rapidly in the FU5 and slowly in the HepG2 cells. Viability was strongly diminished in the HTC and FU5 cells in the presence of fructose, whereas in the HepG2 cells no effect of fructose on viability was detectable. In contrast to the hepatoma cells, rat and human hepatocytes exhibited higher rates of anaerobic glycolysis in the presence of fructose and thus were able to maintain their viability under these conditions. These differences in glycolytic capacity, energy metabolism and hypoxia tolerance of hepatoma cells compared with hepatocytes may be used for the treatment of liver cancer by isolated liver perfusion and ex situ revision of the organ.

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A quantitative estimation of the rust fungus in infected wheat leaves was possible following enzymatic hydrolysis of the chitin and colorimetric determination of the N-acetyl-glucosamine released. The apparently complex cell wall structure of the fungal structures made it necessary, however, to use an enzyme mixture of chitinase and cellulase in order to make accessible the chitin of the cell wall for diges­tion by chitinase. In applying this method the measurement is not appreciably influenced by already formed uredio-spores as would otherwise be the case were the chitin to be determined on the basis of glucosamine after chemical hydrolysis.

The model hepatotoxin carbon tetrachloride (CCl4) was used to study haloalkane free radical-induced lipid peroxidation in isolated rat hepatocytes at steady state oxygen partial pressures (pO2) between 0.2 and 100 mmHg. Equilibrium oxygen conditions were achieved by using an oxystat system. Monitoring of hepatocellular oxygen uptake, malondialdehyde-formation and low-level chemiluminescence during incubations of CCl4-supplemented hepatocytes indicated a drastic stimulation of lipid peroxidation at pO2-levels between 1 and 10 mmHg. Above and below this pO2-region the potency of CCl4 to induce lipid peroxidation sharply decreased. The evaluation of cellular damages by determining trypan blue exclusion and lactate dehydrogenase leakage revealed that in the presence of CCl4 hepatocellular injury was significantly increased at those pO2-levels which were optimal for CCl4-mediated lipid peroxidation. The present results demonstrate that CCl4 is a potent inducer of lipid peroxidation also in the intact hepatocyte, provided that the pO2 is maintained at distinct low levels. The coincidence of lipid peroxidation and loss of cell viability at the same pO2-range provides further evidence for the assumption that the haloalkane-mediated liver cell injury is due to a peroxidative process which primarily occurs at the hypoxic end of the physiological pO2-levels (1-70 mmHg) in liver.