The effect of M-CSF administration on the platelet counts of eusplenic and asplenic SW mice. M-CSF, 2 mg/kg/d, was administered for 5 days, in two daily IP injections, 8 hours apart, to normal mice, or mice that had been splenectomized at least 4 weeks previously. Blood samples were obtained immediately before the morning M-CSF injection on days 1 to 5. The mean ± 1 SE is shown. The number of determinations at each time point was at least 3, and usually ranged from 4 to 28 (mean, 12).