Figure 2. Detection of extra- and intracellular AFMK (A) and melatonin (B). Levels of AFMK were higher in keratinocytes preincubated with melatonin than in control cells (no melatonin added) (A). AFMK was also higher in supernatants that had been preincubated with melatonin, than without melatonin preincubation (A, insets). In both conditions and compartments, levels of AFMK increased. Melatonin, in contrast, showed reduced intracellular levels after UV exposure (B), whereas extracellular melatonin levels in the condition of melatonin preincubation showed no reduction (B, inset). Columns represent means of absolute AUC-values of absorbance peaks from two experiments. Values above columns represent percentage mean ± SEM of unirradiated control.