The relationship between two IGF-1 analogs, IGF-1 LR3 and des(1-3)IGF-1

The two analogs of IGF-1, IGF-1 LR3 and des(1-3)IGF-1, are both based on modified versions of insulin-like growth factor-1 (IGF-1), designed to improve its biological activity and effect. The main differences between them are as follows.

IGF-1 LR3 (Long Acting version)

Structural characteristics: On the basis of natural IGF-1, IGF-1 LR3 replaces the third position of glutamic acid with arginine, while introducing 13 additional amino acid sequences in the n-terminal, which increases its molecular weight.

Biological activity: IGF-1 LR3 has a significantly extended half-life (typically up to 20-30 hours) because its modification makes it more difficult to bind to IGFBPs (IGF-binding proteins). This increases its circulation time and bioavailability in the body.

Uses: People commonly use IGF-1 LR3 to promote muscle growth and enhance protein synthesis because it can stay in the body longer and act on a wider range of tissues.

Des(1-3)IGF-1

Structural Features: After removing the first three amino acids from the N terminal of IGF-1, the analogs Des(1-3)IGF-1 produced, hence the name "des(1-3)". This modification makes it difficult to combine with IGFBPs.

Bioactivity: des(1-3)IGF-1 has a shorter half-life than IGF-1 LR3, usually only a few minutes to an hour, but its bioactivity enhance by 5 to 10 times because it binds more efficiently to the IGF-1 receptor and promotes tissue growth and repair more quickly.

Uses: Due to its extremely high activity and short-acting properties, des(1-3)IGF-1 is more commonly used in situations requiring rapid repair and short-time growth signals, such as rapid recovery after muscle injury.

In SUMMARY

IGF-1 analogs IGF-1 LR3: Long-lasting, longer acting, suitable for sustained muscle growth and metabolic regulation.

IGF-1 analogs Des(1-3)IGF-1: Highly bioactive, although the action time is short, but it can work quickly, suitable for acute repair or applications requiring stronger stimulation.

The main difference between the two is their half-life and the way they interact with the IGF-1 receptor and binding proteins, but both are able to simulate the role of IGF-1 to promote cell growth and metabolism.