How does it work?
IGF-1 binds the IGF-1 receptor and activates signalling pathways such as PI3K/Akt and ERK/MAPK. The LR3 variant is designed to have lower affinity for IGF-binding proteins, which can make the signal more available in certain in vitro systems. Research therefore often concerns growth, differentiation and metabolic signalling in cells or tissue.
Technical mechanism
Modified IGF-1 analogue with reduced binding to IGF-binding proteins. Used primarily in cell and tissue models of IGF-1R signalling.
What is being researched?
- IGF-1R signalling in cell culture
- Follicle development and tissue models in vitro
- Cardiomyocyte proliferation and growth signalling
- Differences between IGF-1 and analogues with altered binding to IGF-binding proteins
About the evidence: The literature for IGF-1 LR3 is narrow and often in vitro. It should not be presented as clinical documentation, but as research on IGF-1R signalling and model-dependent bioactivity.
Research profile
Studies and sources
The links go to independent research databases (PubMed, PubMed Central, ClinicalTrials.gov). The studies are in English and open in a new tab.
IGF-1R signalling and cell models
Studies use IGF-1 or Long R3 IGF-I to investigate growth signalling in cells and tissue.
- Effects of IGF-I bioavailability on bovine preantral follicular development in vitro PreclinicalPubMed· 2007
This in vitro study investigated how Long R3 IGF-I and recombinant IGF-I affected the development of bovine preantral follicles. The study is relevant to IGF-I bioavailability in tissue models, not clinical use.
- Extracellular signal-regulated kinase and phosphoinositol-3 kinase mediate IGF-1 induced proliferation of fetal sheep cardiomyocytes PreclinicalPubMed· 2003
This study investigated how IGF-1 affects proliferation in foetal sheep cardiomyocytes through the ERK and PI3K signalling pathways. It provides mechanistic background for IGF-1R signalling, but does not apply directly to use of the LR3 product in humans.