Fig. 1

Spermine uptake in human monocytes is increased by LPS stimulation. Human monocyte cultures were treated with LPS (100 ng/ml) or vehicle PBS for 0 to 24 hr (a) or for 2 hr (b), then incubated with the indicated concentration of spermine with ¹⁴C-labeled spermine tracer at either 4°C or 37°C for 25 min. Cell-associated radioactivity (CPM) was measured on a Packard microplate scintillation counter, and spermine uptake (CPM) is expressed as the difference between cell-associated radioactivity at 37°C and that at 4°C at each spermine concentration. Results are the mean of spermine uptake ± SE.