Endothelin-2, human is a 21-amino acid vasoactive peptide that binds to G-protein-linked transmembrane receptors, ET-RA and ET-RB. ET-RA, ET-RB[1]
At nanomolar concentrations, Endothelin-2 exhibits a strong and long-lasting vasoconstrictor activity characteristic of endothelin (EC50=0.52 nM)[1]. 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[2].
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[1].
[1]. Grimshaw MJ, et al. Endothelin-2 is a macrophage chemoattractant: implications for macrophage distribution in tumors. Eur J Immunol. 2002 Sep;32(9):2393-400.