What is the Origin of Irisin?

Irisin was first discovered and named in 2012 by a research team at Harvard Medical School, marking a significant advancement in the understanding of exercise endocrinology. The name is etymologically derived from Iris, the Greek messenger goddess, symbolizing its function as a molecular messenger relaying signals from the muscle to other metabolic organs. Its discovery helped to solidify the concept of muscle as an active endocrine organ.

What is the Mechanism of Irisin?

The myokine is produced through the cleavage of its precursor protein, FNDC5 (Fibronectin type III domain-containing protein 5), which is embedded in the muscle cell membrane, and is then released into the systemic circulation. Its mechanism involves binding to specific receptors on white adipocytes, initiating an intracellular signaling cascade that drives the transcriptional program for uncoupling protein 1 (UCP1). This process of fat browning enhances mitochondrial uncoupling, leading to improved glucose homeostasis and systemic insulin sensitivity.

Irisin ∞ Area

Irisin

Meaning

Irisin is a polypeptide hormone, classified as a myokine, that is synthesized and secreted by skeletal muscle tissue into the bloodstream primarily as a direct physiological response to physical exercise, particularly bouts of resistance or endurance training. This myokine plays a critical endocrine role in mediating inter-organ communication, acting as a messenger to transmit the beneficial metabolic effects of exercise to distant tissues. It is widely recognized for its ability to promote the metabolic “browning” of white adipose tissue, thereby increasing systemic energy expenditure and thermogenesis.