HEMIN OR BUTYRATE INCREASES CONSTITUTIVE ERYTHROPOIETIN FORMATION BY MOUSE ERYTHROLEUKEMIA CELL-LINES

The murine erythroleukemic cell lines NN10 and IW32 secrete erythropoi etin (Epo) constitutively. Although both cell lines have Epo receptors (Epo-R), they do not respond to external Epo to undergo erythroid dif ferentiation. In both cell lines, hemoglobin synthesis can be induced by hemin or butyrate. We report here on the effects of these two induc ers on Epo production by the same cell lines. Both hemin and butyrate caused a three- to five-fold increase in Epo secretion on a percell ba sis. The effects were dose- and time-dependent, as was found previousl y for hemoglobin synthesis. The mechanism of the effect on Epo secreti on is posttranscriptional, since the steady-state level of Epo mRNA wa s not altered by the inducers.