IGF-2

Where it comes from

Made in

Liver and most tissues before birth; the liver mainly after

Sent out by

Steady; not under growth hormone in adults

Acts on

• Fetal tissues
• Muscle
• Tumours that make it

What it does

• Drives fetal and placental growth ¹
• Supports muscle repair and regeneration
• Circulates in adults at three times the level of IGF-1, with no settled job

In medicine

• Too much IGF2 expression causes the overgrowth of Beckwith-Wiedemann syndrome; too little, Silver-Russell syndrome ¹
• Tumours that secrete an incompletely processed “big IGF-2” cause hypoglycaemia, because it escapes the binding proteins and acts on the insulin receptor ²

Beyond the body’s own use

• Not used as a medicine: there is no IGF-2 product, and the clinical problem it causes is too much of it rather than too little
• Blocking it is the direction of interest, in the cancers that make it, and that work is at the stage of antibodies and receptor inhibitors rather than trials ²
• In rodents, injected IGF-2 strengthened recall and the effect lasted weeks, which made it a memory candidate ³. It has not been tested in people, and the imprinting that controls the gene makes any attempt to raise it in a person a long way off