Evidence for the role of leukotrienes C4 and D4 as essential intermediates in CSF-stimulated human myeloid colony formation.

Products of the lipoxygenation of arachidonic acid have been shown to induce a variety of effects on cells of myeloid lineage. Colony-stimulating factor causes release of arachidonic acid from cell membranes, which then undergoes oxygenation via the cyclooxygenase and lipoxygenase pathways. Nordihydroguaiaretic acid (NDGA) and 3-amino-1-[m(trifluoromethyl)-phenyl]-2-pyrazoline (BW 755C), compounds that inhibit both the cyclooxygenase and lipoxygenase pathways, cause dose-dependent inhibition of CSF-induced human granulocyte-monocyte colony formation in vitro, with complete inhibition at 20 and 50 microM, respectively. Indomethacin, which inhibits cyclooxygenase but not lipoxygenase, has no effect on colony growth at 50 microM, which is well in excess of the dose needed for complete inhibition of cyclooxygenase. Leukotrienes (LTs) C4 and D4 (5-100 ng/ml) reverse NDGA inhibition of colony growth. At similar concentrations, neither leukotriene B4 or 5-HETE caused reversal of NDGA inhibition. These results support a role for LTC4 and LTD4 as essential intermediates in CSF-stimulated myeloid colony formation.