Insulin-like growth factor 1 is a peptide hormone involved in cellular growth, protein synthesis, tissue repair, skeletal development, metabolic regulation, and anabolic signaling. IGF-1 mediates many of the growth-promoting effects associated with growth hormone and functions as a major endocrine regulator of tissue growth and cellular adaptation.
The hormone stimulates amino acid uptake, protein synthesis, cell proliferation, survival signaling, and tissue remodeling pathways. IGF-1 also influences skeletal muscle growth, bone metabolism, nervous system development, glucose utilization, and mitochondrial activity. Through activation of intracellular growth pathways, IGF-1 contributes to coordination between nutrient availability, endocrine signaling, and long-term tissue maintenance.
IGF-1 is produced primarily by the liver in response to growth hormone stimulation. Additional local production occurs within skeletal muscle, bone, brain, adipose tissue, and numerous peripheral tissues where IGF-1 can function through autocrine and paracrine signaling mechanisms.
The hormone is synthesized as a peptide precursor encoded by the IGF1 gene and circulates bound to insulin-like growth factor binding proteins that regulate stability and tissue availability. Nutritional status strongly influences hepatic production because adequate amino acid and energy availability support growth hormone-mediated synthesis.
IGF-1 production is regulated mainly by growth hormone signaling through the growth hormone receptor and JAK-STAT pathways within hepatic tissue. Nutrient availability, insulin signaling, protein intake, sleep physiology, circadian rhythm, exercise, age, and inflammatory cytokines also influence production.
IGF-1 acts through the IGF-1 receptor, a receptor tyrosine kinase that activates PI3K-AKT signaling, MAP kinase pathways, mTOR signaling cascades, and anti-apoptotic mechanisms. Binding proteins regulate circulating half-life and tissue delivery. Negative feedback from IGF-1 can suppress growth hormone secretion at both hypothalamic and pituitary levels. Through these integrated anabolic endocrine systems, IGF-1 coordinates growth signaling, tissue maintenance, metabolic adaptation, and cellular repair processes.
IGF-1 contributes to cellular growth, tissue repair, and metabolic recovery signaling.
