What is the Origin of Myokine Secretion?

The recognition of skeletal muscle as a fully functional endocrine organ, capable of secreting these bioactive signaling molecules, represents a significant paradigm shift in the fields of exercise physiology and endocrinology, with the term "myokine" formally introduced in the early 2000s to categorize these muscle-derived factors. This discovery expanded the traditional view of hormonal signaling.

What is the Mechanism of Myokine Secretion?

The mechanism is initiated by the mechanical stress and metabolic demands of muscle contraction, which trigger an intracellular cascade involving calcium flux and energy depletion. This stimulus activates specific gene transcription programs within the muscle cell, resulting in the synthesis and secretion of various myokines, such as Irisin and certain isoforms of Interleukin-6. Once circulating, these powerful peptides exert pleiotropic systemic effects: they enhance insulin receptor sensitivity in peripheral tissues, promote beneficial metabolic shifts in adipose tissue, and can cross the blood-brain barrier to stimulate neurotrophic factor production, thereby positioning myokine secretion as a central mechanism for maintaining whole-body hormonal and metabolic health.

Myokine Secretion

Meaning

Myokine Secretion describes the essential biological process where contracting skeletal muscle fibers actively synthesize and release specialized signaling peptides, termed myokines, directly into the systemic circulation, particularly during and immediately following physical exertion. These myokines function as crucial endocrine or paracrine messengers, facilitating vital communication between the muscle tissue and distant organs, including adipose tissue, the liver, and the central nervous system. This process establishes muscle as a critical endocrine organ that profoundly influences systemic metabolic regulation and anti-inflammatory homeostasis.