FIGURE 6. Recycling of ¹²⁵I-EGF.

(A) Incubation steps in the experimental protocol to measure recycling of ¹²⁵I-EGF. (B) NIH 3T3/EGFR cells were incubated with 5 ng/mL ¹²⁵I-EGF for 5 min at 37 °C, surface ¹²⁵I-EGF was removed by the mild acidic buffer wash, and the recycling assay was performed as described in Section 4.5. The chase incubation medium was supplemented or not with 300 µM primaquine.