Adult male zebrafish; H&E staining coronal view

On coronal sections, the pituitary (or hypophysis) can be found in the midplane, at the level of the dorsal hemisphere of the eyes. Most of the pituitary is enclosed in an excavation of the skull, although this enclosement may be very thin over some parts. On more dorsal sections, the brain can be seen in front of the pituatary.

At this level, the following structures can be identified:

• pseudobranch and gill, laterally;
• musculature: the adductor muscle of the opercle (gill cover); note that these muscles are attached to skull protuberances, and the eye internal rectus and external rectus muscles;
• retrobulbar venous plexus and optic nerves.

Adult male zebrafish; H&E staining sagittal view
On mid-sagittal sections, the pituitary can be found in the roof of the oropharynx. The pituitary resides in an excavation of the skull, and it is connected to the brain by a stalk.
Note the optic chiasm, located rostral from the pituitary.