Table 1.

Relative ligand binding affinity of IR isoforms, IGF-IR, and HRs containing either IR-A (HR-A) or IR-B (HR-B) moieties.

Receptor	Insulin	IGF-II	IGF-I	Reference
IR-A	++++	+++	+/++	Yamaguchi et al. (1993), Frasca et al. (1999), Benyoucef et al. (2007)
IR-B	++++	+−/+	−	Yamaguchi et al. (1993), Frasca et al. (1999), Benyoucef et al. (2007)
IGF-IR	−	+++/++++	++++	Pandini et al. (2002), Denley et al. (2004), Benyoucef et al. (2007)
HR-A	−/++	+++/++++	+++/++++	Pandini et al. (2002), Slaaby et al. (2006), Benyoucef et al. (2007)
HR-B	−	++/++++	+++	Pandini et al. (2002), Slaaby et al. (2006), Benyoucef et al. (2007)