IGF-1 LR3: Growth Factor Research Overview
IGF-1 LR3 is a long-acting analogue of insulin-like growth factor-1 widely used in cell biology and metabolic research. Here is what Canadian researchers need to know.
What Is IGF-1 LR3?
IGF-1 LR3 (Insulin-like Growth Factor-1 Long R3) is a modified synthetic analogue of human IGF-1. The "Long R3" designation refers to structural modifications that significantly extend its half-life compared to native IGF-1.
Native IGF-1 has a short circulating half-life due to its high affinity for IGF binding proteins (IGFBPs), which sequester it in the bloodstream. IGF-1 LR3 features an arginine substitution at position 3 and an N-terminal glutamic acid extension that reduces IGFBP binding by approximately 1000-fold, resulting in substantially prolonged biological activity.
Mechanism of Action
IGF-1 LR3 activates the IGF-1 receptor (IGF1R), a receptor tyrosine kinase that initiates several downstream signalling cascades:
**PI3K/Akt pathway**: Associated with cellular survival, glucose uptake, and protein synthesis. Activation of this pathway has been extensively studied in the context of muscle cell biology and metabolic regulation.
**MAPK/ERK pathway**: Involved in cell proliferation, differentiation, and gene expression. IGF-1 receptor signalling through MAPK has been studied in developmental biology and cancer research.
**mTOR activation**: The mammalian target of rapamycin integrates growth factor signals with nutrient sensing. IGF-1R/Akt-mediated mTOR activation is a key node in anabolic signalling research.
Research Applications
IGF-1 LR3 is widely used across several research disciplines:
**Cell biology**: As a growth factor supplement in cell culture media, particularly for satellite cells, myoblasts, and other cell types that express high levels of IGF1R
**Muscle physiology research**: Studies examining protein synthesis, muscle fibre hypertrophy, and satellite cell activation in animal models
**Metabolic research**: Investigation of glucose uptake, insulin sensitisation, and the intersection of the IGF-1 and insulin signalling pathways
**Cancer biology**: Given IGF1R's role in tumour cell survival and proliferation, IGF-1 LR3 is used as a reference agonist in oncology research
Considerations for Researchers
The extended half-life of IGF-1 LR3 compared to native IGF-1 makes it particularly useful for in vivo research where sustained receptor activation is required. However, researchers should account for its prolonged activity when designing experimental protocols.
Popular Peptides supplies IGF-1 LR3 (1mg) as a research-grade compound with independent purity verification and Certificate of Analysis.
Important Notice
For research use only. Not intended for human or veterinary therapeutic application.