At nanomolar concentrations, Endothelin-2 exhibits a strong and long-lasting vasoconstrictor activity characteristic of endothelin (EC
50
=0.52 nM).
Endothelin-2 is a chemoattractant for macrophages and THP-1 monocytic cells, but not for freshly isolated monocytes. The chemotactic response to Endothelin-2 shows a typical bell-shaped response curve. Experiments with endothelin receptor antagonists shows that migration to Endothelin-2 is mediated via the ET-RB receptor. Endothelin-2 expression by tumors may modulate the behavior of macrophages such that activated cells accumulate in areas of hypoxia.
Two distinct phases of pressor effects are typically seen in response to Endothelin-2: the early phase immediately follows the depressor response and dominates during the next 3-10 min, whereas the late pressor effect develops 10-20 min after the injection and lasts >1 hr.
