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

Lactate dehydrogenase (LDH) release in 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 microL of cellular homogenates and 150 microL of media. The parallel processing of samples and smaller volumes used in the fluorescence assay results in decreased analysis time and costs.