ROLE OF INTERLEUKIN-3 IN THE REGULATION OF INTERCELLULAR K-CELLS( HOMEOSTASIS IN CULTURED MURINE HEMATOPOIETIC)

Comparative fluorimetric, flow cytofluorimetric and fluorescence ratio metric determinations of intracellular K+ concentrations in murine hae mopoietic cells (FDCP-Mix clone A4) cultured in the presence and absen ce of the specific growth factor Interleukin-3 were carried out with t he fluorescent potassium-binding benzofuran-isophthalate acetoxymethyl ester probe. Cell suspensions kept in the absence of Interleukin-3 fo r 5 hours exhibited lower fluorescence intensities and smaller fluores cence ratios than their growth-factor-replete counterparts, an effect found to be reversible by readdition of the growth factor. It is concl uded that Interleukin-3 deprivation of-these cells leads to loss of in tracellular K+. It is tentatively suggested that this deprivation-indu ced K+ loss might be associated with an early event in apoptotic cell death. (C) 1995 Academic Press, Inc.