A new candidate for the regulation of erythropoiesis

Abstract

The effect of pure human insulin‐like growth factor I (IGF I) on the colony formation of late stage erythroid precursor cells (CFU‐e) from fetal mouse liver and adult bone marrow was studied in a serum‐free culture system. We found that IGF I in physiological concentrations stimulated erythroid colony formation. The combined effect of IGF I and erythropoietin was smaller than the sum of their single effects. The number of colonies induced by IGF I was linearly dependent on the number of plated cells. Our results indicate that IGF I is the first early defined mitogen that stimulates the late stages of erythroid differentiation independently of erythropoietin.