Energy-dependent reduction of pyruvate to lactate by intact isolated parenchymal cells from rat liver
Summary Morphologically intact isolated parenchymal cells obtained from the livers of fasted rats formed lactate from added pyruvate at a linear rate. Reducing equivalents necessary for this lactate production were derived from the oxidation of a portion of the added pyruvate. Lactate formation was greatly reduced by anaerobiosis and by inhibitors of electron transport, uncoupling agents or oligomycin. These results indicate that the transfer of reducing equivalents from mitochondria to cytoplasm in intact liver cells is an energy-coupled process and provide evidence that energy-linked reversed electron transport is of physiological significance in animal tissues.
A recurring problem in forensic medicine is the need to fix the time of death within the limits of probability. Errors in overestimating and underestimating the post-mortem interval based on body cooling is common. Post-mortem biochemistry has become a potent additional procedure in forensic death investigation. However, in our experiment, to determine the post-mortem interval we investigated the ATPase activity. The investigation was performed on the liver tissue of 25 corpses (21 men and four women) of age ranging between 40–60 years. The study of ATPase enzymatic activity shows that there is a considerable drop in the levels of ATPase activity with increasing post-mortem interval up to 24 h and this is one of the most reliable methods for estimating time of death.