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Two complications of the receptor family that bear on everything IGF-1 does

Published 26 October 2026 · REVIVE LAB UAE Research Desk · 5 min read
The insulin receptor gene is alternatively spliced at exon 11, giving isoform B, the metabolic receptor of liver, muscle and fat, and isoform A, lacking twelve residues, which binds IGF-2 with high affinity and is expressed in fetal tissue and re-expressed in many cancers — Frasca and colleagues characterised this in 1999. Separately, because the insulin and IGF-1 receptors are each dimers assembled from half-receptors, cells expressing both make hybrid receptors with one half of each; hybrids bind IGF-1 with high affinity and insulin poorly, so they function as additional IGF-1 receptors. Both complications shape how IGF-1 and its analogues act in any tissue.

Isoform A

Twelve residues near the carboxyl terminus of the alpha subunit are included or skipped. Including them, isoform B, gives a receptor selective for insulin. Skipping them, isoform A, gives one that also binds IGF-2 and signals more toward growth than metabolism. Fetal tissues use isoform A, which is how IGF-2 drives fetal growth through an insulin receptor; many tumours revert to it.

The failed IGF-1 receptor antibodies did not block it, which is part of why they failed.

Hybrids

In a cell expressing both receptors, half-receptors assemble randomly, so a substantial fraction can be hybrid. Hybrids bind IGF-1 at near-native affinity and insulin at about a tenth, and signal like IGF-1 receptors. Their proportion depends on the relative expression of the two receptors and differs between tissues and between normal and insulin-resistant states.

They are one reason that insulin resistance and IGF-1 action are entangled.

For the analogue

IGF-1 LR3 acts on the IGF-1 receptor and on hybrids, as IGF-1 does, and weakly on the insulin receptor. Its binding-protein escape does not change which receptors it reaches, only how much of it does.

IGF-1 LR3 is supplied by REVIVE LAB UAE for laboratory research use only, with identity and purity documented for the batch. It is not for human or veterinary use, and no dosing, administration or protocol guidance is provided.

What it costs

FormatStrengthPriceAvailability
IGF-1 LR3 Pack1 mgAED 650In stock

Delivery is AED 40 flat and free on orders over AED 700. Payment is cash on delivery anywhere in the UAE, or USDT (TRC20) in advance, which takes 5% off the order total.

Frequently asked

Isoform A?

Twelve residues near the carboxyl terminus of the alpha subunit are included or skipped. Including them, isoform B, gives a receptor selective for insulin. Skipping them, isoform A, gives one that also binds IGF-2 and signals more toward growth than metabolism. Fetal tissues use isoform A, which is how IGF-2 drives fetal growth through an insulin receptor; many tumours revert to it.

Does REVIVE LAB UAE provide dosing guidance?

No. REVIVE LAB UAE supplies research materials and provides no dosing, administration or protocol guidance of any kind. Every product is sold for laboratory research use only and is not for human or veterinary consumption.

How fast is delivery in the UAE?

Stock is held in Dubai. An order confirmed before 4 PM Dubai time is dispatched the same working day, reaching Dubai and Abu Dhabi the same day and the remaining emirates within 24 hours. Delivery is AED 40 flat and free over AED 700.

IGF-1 LR3 Pack — in stock, dispatched from Dubai
HPLC-verified, lot certificate on every carton, 24-hour delivery nationwide. Browse the catalogue → All peptides UAE

Related reading

→ IGF-1 LR3 Pack — 1 mg → IGF-1 and the insulin receptor → The IGF-1 receptor, cloned 1986

Supplied for laboratory research use only. Not for human or veterinary consumption. REVIVE LAB UAE provides no dosing, administration or protocol guidance.