A rapid beta-NADH-linked fluorescence assay for lactate dehydrogenase in cellular death

Lactate dehydrogenase (LDH) release is a common marker of cellular death. Traditionally, the fraction of LDH released has been measured using a NADH-linked UV-Vis spectrophotometric method, The limitation of this method is that samples are usually run serially and thus is time intensive. Therefore, we developed a NADH-linked LDH assay using a fluorescence plate reader that had a correlation of 0.95 with the traditional UV-Vis spectrophotometric method. Using rabbit renal proximal tubule suspensions at a concentration of 1 mg cellular protein/ml of media, the fluorescence assay can determine LDH release in 22 samples in 2 min using 12 mu L of cellular homogenates and 150 mu L of media. The parallel processing of samples and smaller volumes used in the fluorescence assay results in decreased analysis time and costs.