Figure 4.
Removal of tryptophan from the C terminus renders ET-1 nontoxic for mast cell–deficient mice. Synthetic peptides of ET-1 (1–21; A) or of ET-1 minus tryptophan in position 21 (1–20; B) were injected intraperitoneally into mast cell–deficient KitW/Wv mice, and the body temperature was followed by rectal measurements at indicated time points. Mast cell–deficient KitW/Wv mice were resistant to ET-1 (1–20), but succumbed to ET-1 (1–21).