Relative Affinities for Receptors of the Insulin Family to Family Members
 

Receptor	Relative Affinities
Insulin	Insulin >Proinsulin (10%) >IGF II >IGF I >>Relaxin(~0)
IGF I	IGF I > IGF II >Insulin ~ Proinsulin
IGF II	IGF II = IGF I >>Insulin ~ Proinsulin
Relaxin	Relaxin >NGF >Proinsulin > IGF >>Insulin (~0)
NGF	NGF (only)