GRO (Growth Related Oncogene) belonging to IL-8 family is polypeptide which has three isoforms α, β and γ, and it inhibits proliferation of endothelial cells. GRO/CINC-1 (cytokine-induced neutrophil chemo attractant 1) was originally purified from media conditioned by IL-1β stimulated rat kidney epithelioid cells (NRK-52E.) Amino acid sequence that encodes rat CINC-1 was identified in 1989 by Watanabe’s group at Toyama Medical and Pharmaceutical University. CINC-1 is a member of the alpha (CXC) subfamily of chemokines. Three additional rat CXC chemokines (CINC-2α, CINC-2β, CINC-3/MIP-2) have been identified. The protein sequence of CINC-1 is 63 - 67% identical to that of CINC-2α, CINC-2β and CINC-3/MIP-2. In addition, each of GROα, GROβ and GROγ is sharing 68%, 71% and 69% identity with CINC-1. This has been suggested that CINCs are the rat counterparts of human GROs.