Ultrastructural effects of granulocyte colony stimulating factor (G-CSF) and macrophage colony stimulating factor (M-CSF) on rat neutrophils and monocytes

Human granulocyte colony stimulating factor (G-CSF) and macrophage colony stimulating factor (M-CSF) were administered intravenously to rats, and their effects on neutrophils and monocytes were examined by electron microscopy. G-CSF increased the number of cytoplasmic granules in neutrophils. It also enhanced maturation of the nuclear shape in the neutrophils, while chromatin condensation and peroxidase distribution remained immature. M-CSF induced proliferation of monocytes in peripheral blood and bone marrow, but did not affect morphology or distribution of peroxidase reactivity. This study was presented at the 25th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Matsumoto, September 28–30, 1993.