Time-dependent degradation of ¹²⁵I-rhTPO by human PRP. PRP was incubated with ¹²⁵I-rhTPO for 1 to 120 minutes at 37°C. Platelet-associated radioactivity (n = 2 per timepoint) was then analyzed by SDS-PAGE and autoradiography. Nonincubated ¹²⁵I-rhTPO dosing solution (DS) was also run in the last lane of the gel. Time is indicated on the top of the figure and approximate MW (determined from prestained MW markers) is presented on the right axis.