GM-CSF and IL-3 stimulate diacylglycerol generation in murine bone marrow-derived macrophages

In murine bone marrow-derived macrophages, prelabeled with either 3H]myristic acid or 3H]arachidonic acid, the mitogenic colony stimulating factors GM-CSF and IL-3 stimulated a transient increase in 3H]diacylglycerol generation. Maximum 3H]diacylglycerol levels were detected at 10-15 min. The stimulation of 3H]diacylglycerol generation was dependent on the concentration of CSF and correlated with their ability to activate a variety of processes in the macrophage, including DNA synthesis. This is the first report to demonstrate that GM-CSF elevates diacylglycerol levels in macrophages and also to show that diacylglycerol generation may be an important signaling mechanism for IL-3 action. In conjunction with our recent demonstration that the mitogenic agents CSF-1, 12-0-tetradecanoylphorbol-13-acetate and exogenous phospholipase C also stimulate diacylglycerol generation in the macrophage (Veis and Hamilton, J.Cell.Physiol., 147, 298-305, 1991), our findings suggest that an increase in diacylglycerol levels is necessary but not sufficient for macrophage proliferation.