Abstract
Specific insulin-like growth factor I (IGF-I) receptors on human promyelocytic leukemia cell line (HL-60) were identified and characterized.[125I] IGF-I specifically bound to the cells, and PIJIGF-I binding to the cells was displaced by unlabeled IGF-I in a dose dependent manner.[125I] IGF-I binding to the cells were displaced by multiplication stimulating activity (MSA) and porcine insulin, with potencies that were10and100times less than that of IGF-I, respectively. By an affinity labeling technique, IGF type I receptors were found to be present on the HL-60cells.
After the cells were differentiated to the macrophage-like cells by 12-o-tetra-decanoyl-phorbol-13-acetate (TPA) and1, 25-dihydroxy-vitamin D3 (1, 25 (OH) 2D3), [125I] IGF-I binding to the cells decreased significantly. By Scatchard analysis, it was found to be due to a decrease in the number of IGF-I receptors.
Thus, the differentiation of HL-60cells to the macrophage-like cells was accompanied by a decrease in IGF-I receptors.
