The adipokines, or adipocytokines (Greek adipo-, fat; cytos-, cell; and -kinos, movement) are cytokines (cell signaling proteins) secreted by adipose tissue. The first adipokine to be discovered was leptin in 1994. Since that time, hundreds of adipokines have been discovered. The adipokines, or adipocytokines (Greek adipo-, fat; cytos-, cell; and -kinos, movement) are cytokines (cell signaling proteins) secreted by adipose tissue. The first adipokine to be discovered was leptin in 1994. Since that time, hundreds of adipokines have been discovered.