Cardiotrophin-1, also known as CT-1 and CTF1, is a member of the IL-6 superfamily. It is a sreted cytokine that is expressed in heart, skeletal muscle, prostate and ovary, and to lower levels in lung, kidney, pancreas, thymus, testis and small intestine. The protein exerts its cellular effects by interacting with the glycoprotein 130 (gp130)/leukemia inhibitory factor receptor beta (LIFR) heterodimer. In addition, CT-1 activates phosphatidylinositol 3-kinase (PI-3 kinase) in cardiac myocytes and enhances transcription factor NF-κB DNA -binding activities.