High sequence homology allows all three receptors to bind IGF1, IGF2, and insulin, but with differing affinities, indicated by gradients. IR-A and IR-B differ by inclusion of exon 11 (E11) only in IR-B. Different ligand binding affinities and downstream signaling intermediates, confer the different functional outcomes indicated. For small intestine these are still putative outcomes since neither expression patterns nor specific functions of IGF1R, IR-A and IR-B are defined.