Figure 7.

Generation and release of lactate in isolated proximal tubules subjected to hypoxic-reoxygenation (H/R) injury in the presence and absence of glycine. As shown in left panel, 15 minutes of hypoxia and 15 minutes of reoxygenation caused an approximately fourfold increase in total lactate levels (tubule pellet+media lactate content). This lactate generation occurred in the presence or absence of 2 mM glycine, which prevented hypoxic cell death (right panel). Almost all of the generated lactate was found in the tubule culture medium, indicating the rapid release of lactate. Again, it occurred in the presence or absence of lethal membrane injury, given that glycine did not block lactate efflux. These results were obtained with four separate, isolated tubule preparations.