Suppressive effect of acetylsalicylic acid on erythropoietin-responsive cells in mice.

The time-response curve for RBC-59Fe uptake following i.p. injections of 3 doses of 5 mg of acetylsalicylic acid (ASA) at 4 hour interval into normal, nonpolycythemic mice, shows a maximal depression (35% of normal) at 3 days after ASA with return to almost normal values by 7 days. The effect is dose-related, showing a plateau with doses of ASA above 5 mg/4 hr. The shape of the time-response curve indicates that the more mature cells in the erythron are not affected by ASA and that the major effect of the drug must be on earlier erythroid cells. Administration of ASA prior to administration of erythropoietin (Epo) into post-hypoxic polycythemic mice depresses the incorporation of 59Fe into erythrocytes. The depression of radioiron uptake is similar when ASA is given prior to or simultaneously with Epo. When ASA is given 24 hr after injection of Epo, suppression is less marked. These results suggest a suppressive effect of the drug on the erythropoietin-responsive cells (ERC).