Down regulation and recovery of the epidermal growth factor receptor in serum supplemented versus defined medium.

The down regulation of surface membrane receptors for 125I) epidermal growth factor (EGF) has been evaluated in normal and SV40-transformed human fibroblasts (WI38) under conditions of serum-supplemented versus defined growth media. Both normal and transformed WI38 cells down regulate and recover the EGF receptor and these processes do not differ significantly in serum-supplemented versus defined media. These data are in contrast to a recent study that reported that the HeLa cell does not down regulate the EGF receptor in defined media, whereas it does in serum-supplemented media.