Cardiotrophin-1 (CT-1) is a member of the cytokine family which also includes IL-6, IL-11, leukemia inhibitory factor (LIF), oncostatin M (OSM), and ciliary neurotrophic factor (CNTF)[Pennica, 1996 #1320]. CT-1 is a pleiotropic cytokine which is expressed in various tissues including the adult heart, skeletal muscle, ovary, colon, prostate and fetal lung. Studies showed CT-1 which induces cardiac myocyte hypertrophy in vitro can bind to and activate the ILST/gp130 receptor. Human CT-1 encodes a 201 amino acid (a.a.) residue protein that lacks a hydrophobic signal peptide and it shares 78 % a.a. and 80 % a.a. sequence identity with murine and rat CT-1.