FLOW-CYTOMETRIC DETERMINATION OF DEHYDROGENASE-ACTIVITIES IN PRIMARY HUMAN GASTROINTESTINAL TUMOR-CELL LINES

The activities of 6 dehydrogenases, lactate dehydrogenase (LDH), gluco se-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (ICDH), glycerol-3-phosphate dehydrogenase (GDH), succinate dehydrogenase (SD H) and glutamate dehydrogenase (GLDH), determined by means of flow cyt ometry in 13 primary human gastrointestinal tumour cell lines, includi ng 10 esophageal carcinomas, one gastric cancer, and 2 pancreatic canc ers. Two-parametric measurements of specific dehydrogenase activities in single cells were performed with DAPI as fluorochrome for the nucle ar DNA and with the fluorescent redox system of 5-cyano-2,3-ditolyl-te trazolium chloride (CTC) which forms brilliant red formazan crystals u pon reduction by cellular redox enzymes. Furthermore, with the aid of the calibration procedure reported previously [18] the enzyme activiti es were expressed as biochemical units. This application of tetrazoliu m salt technique for demonstrating dehydrogenase activities in human t umour cells by flow cytometry offers an alternative tool to characteri ze malignant tumors.