Irisin is a peptide signaling hormone involved in energy metabolism, skeletal muscle communication, thermogenic adaptation, mitochondrial regulation, and metabolic signaling between muscle and adipose tissue. The hormone is released during muscular activity and participates in communication pathways linking physical movement with systemic metabolic adaptation.
Irisin influences energy expenditure, mitochondrial biogenesis, glucose utilization, lipid metabolism, and thermogenic gene expression within adipose tissue. The hormone also contributes to skeletal muscle signaling, bone communication pathways, and regulation of metabolic flexibility during changing energy demands. Through these actions, irisin functions as an endocrine messenger connecting muscular activity with whole-body metabolic physiology.
Irisin is produced mainly by skeletal muscle through cleavage of the membrane protein FNDC5. Production increases during muscular contraction and exercise-associated signaling. Additional expression occurs in adipose tissue, heart tissue, nervous system structures, and additional metabolic organs.
The hormone is released into circulation where it can act on adipose tissue, skeletal muscle, bone, and additional endocrine-responsive tissues. Local muscle production therefore serves as a key interface between physical activity and endocrine metabolic communication.
Irisin production is regulated by muscular activity, PGC-1alpha signaling, mitochondrial demand, energy metabolism, exercise physiology, oxidative stress pathways, and nutrient availability. Endurance-associated signaling strongly influences FNDC5 expression and irisin release.
Irisin acts through signaling systems associated with thermogenic gene expression, mitochondrial adaptation, metabolic regulation, and adipocyte communication pathways. Interactions with AMPK signaling, oxidative metabolism pathways, and mitochondrial biogenesis systems contribute to its physiological effects. Through these integrated muscle-endocrine signaling systems, irisin coordinates metabolic adaptation, energy expenditure, mitochondrial regulation, and communication between skeletal muscle and peripheral metabolic tissues.
Exercise-stimulated myokine involved in metabolic adaptation signaling
