IGF-1 LR3
Synthetic analogue of insulin-like growth factor 1 (IGF-1) carrying an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. These modifications lower binding to IGF-binding proteins and extend its duration of action relative to native IGF-1. LR3 IGF-1 is primarily an established cell-culture reagent (serum-free media, bioprocessing); it is NOT an approved human medicine. Use in the bodybuilding grey market is described; as an IGF-1 analogue, LR3 IGF-1 falls under the WADA anti-doping prohibition.
Mechanism of action
IGF-1 LR3 is a recombinantly produced variant of human IGF-1. Two changes define its properties: (1) at position 3, glutamic acid is replaced by arginine; (2) a 13-amino-acid sequence is added at the N-terminus ('Long'). Both modifications drastically reduce affinity for the six IGF-binding proteins (IGFBP-1 to -6) that normally bind native IGF-1 in the blood and regulate its availability at the receptor. As a result, a larger fraction of the molecule is freely available to bind the type-1 IGF receptor (IGF-1R) — the same receptor as native IGF-1. In preclinical models and cell culture, LR3 IGF-1 therefore acts as a more potent agonist than unmodified IGF-1. The downstream signalling pathway (PI3K/Akt and MAPK) is identical to that of IGF-1; the modification changes bioavailability, not the receptor target.
Bewijs in één oogopslag
Wat de studies laten zien
Waar studies elkaar tegenspreken
Does the anabolic benefit of IGF-1 LR3 outweigh the theoretical cancer risk?
Farmacokinetiek
Theoretische concentratiecurve bij een halfwaardetijd van 21 h. Puur farmacokinetisch model — geen doseringsaanbeveling.
Open in PK tool →Veiliger gebruik & risico's
Bekende bijwerkingen uit studies
Interacties & combinaties
Risico's & hygiëne-aspecten in de literatuur
Identity and purity problem on the grey market
Stemmen van toezichthouders
All forms of exogenous IGF-1 are prohibited at all times, and any substance containing any form of exogenous IGF-1 should be considered prohibited.
Anekdotische waarnemingen
Juridische status per land
Reconstitutie-calculator
Peptiden komen als droog poeder. Eenmaal opgelost in een vloeistof (reconstitutie) beantwoordt deze calculator één enkele vraag: hoeveel stof zit er daarna in één milliliter oplossing?
- 1Voer de hoeveelheid stof van de flacon in (staat op het etiket).
- 2Voer in hoeveel oplosmiddel je toevoegt.
- 3Resultaat = concentratie in mg per mL.
Begeleidende stoffen
Deze begeleidende stoffen betreffen de peptideklasse, niet een specifiek gebruik. Geen aanbeveling, geen dosering.
Studieregister
Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins is maintained when administered by injection
Long R3 insulin-like growth factor-I (IGF-I) infusion stimulates organ growth but reduces plasma IGF-I, IGF-II and IGF binding protein concentrations in the guinea pig
Insulin-like growth factor I (IGF-I) and long R(3)IGF-I differently affect development and messenger ribonucleic acid abundance for IGF-binding proteins and type I IGF receptors in in vitro produced bovine embryos
Recombinant human insulin-like growth factor I stimulates growth and has distinct effects on organ size in hypophysectomized rats
Bronnen & methode
Ontvang nieuwe studies over IGF-1 LR3
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