IGF-1: The GH Mediator
Insulin-like growth factor 1 (IGF-1) is a 70-amino-acid peptide hormone structurally similar to insulin that mediates many of growth hormone's peripheral effects. Produced primarily by the liver in response to GH stimulation, IGF-1 circulates bound to IGF-binding proteins (IGFBPs) and acts through the type 1 IGF receptor (IGF-1R) to influence cell growth, differentiation, and survival.
The IGF-1R Signaling Cascade
IGF-1R is a receptor tyrosine kinase that, upon ligand binding, activates two major downstream pathways:
- PI3K-Akt-mTOR: Promotes cell survival, protein synthesis, and metabolic regulation
- Ras-MAPK-ERK: Drives cell proliferation and differentiation
These pathways have been extensively investigated in preclinical models for roles in development, metabolism, and aging.
The Longevity Paradox
One of the most intriguing findings in preclinical aging research is that reduced IGF-1 signaling — through genetic mutations or caloric restriction — is associated with extended lifespan in multiple model organisms. This has created a research paradox: while GH/IGF-1 promotes tissue maintenance and repair, attenuated signaling may favor longevity. Research with GH secretagogues like CJC-1295/Ipamorelin helps elucidate this complex relationship.
Research Disclaimer
This article is for educational and informational purposes only. All compounds discussed are intended strictly for in-vitro and preclinical research use. They are not intended for human consumption. Always consult published scientific literature and institutional review protocols before initiating any research program.