Figure 5.

Double immunofluorescence staining of the islet-associated protein (IA-2) family of protein tyrosine phosphatases (PTPs) with serotonin and ghrelin in rat duodenum. Rat duodenal sections were concurrently incubated with anti–IA-2 (A–C and G–I) or anti–IA-2β (D–F and J–L) and anti-serotonin (A–F) or anti-ghrelin (G–L) antibodies. Arrowheads indicate double-immunolabeled gastrointestinal endocrine cells (GECs) and arrows indicate GECs that do not express the IA-2 family of PTPs. Negative control sections were stained with a mixture of anti-rabbit/anti-mouse secondary antibodies without primary antibodies (M–O). Blue fluorescence indicates nuclear counterstaining. Bars, 20 µm.