Metabolic effects of interleukin 3 on 32D cl23 cells analyzed by NMR.

Abstract

31P NMR of living 32D cl23 cells and 1H NMR of cell extracts were used to study the metabolic effects of interleukin 3 (IL3). When IL3 was removed from 32D cl23 for 9-10 hours 31P spectra showed a decrease in sugar phosphate, gamma ATP/ADP, alpha ATP/ADP/NAD, and beta ATP resonances which declined progressively over a time period of up to 16 hours. By comparison, ATP measurements using the luciferin/luciferase method resulted in the decline of ATP levels from 12 hours in the absence of IL3. At this time, viability of the cells was unaffected. For 1H NMR experiments cells were grown in the presence and absence of IL3 for 4 and 24 hours, after which acid cell extracts were prepared. These spectra revealed a four-fold decrease in lactate 4 hours post-IL3 removal. Alanine levels were unchanged but glycine was elevated 1.5-fold whilst various other amino acids were elevated slightly. After 24 hours without IL3, only 22% of cells were viable which was reflected in a general decline of most resonance intensities. These findings suggest that IL3 exerts its effect primarily on glucose metabolism and has a delayed secondary effect on maintenance of ATP levels in the cell. We have demonstrated the applicability of high resolution 1H and 31P NMR to the study of cellular metabolism in hemopoietic cells.