Abstract

The pituitary gland is a critical part of the endocrine master control for the body, and particularly a key player in the pituitary-hypothalamic-gonadal axis, which regulates reproductive function. Due to its location within the cranium, embedded in the sella turcica (the hypophyseal fossa within the sphenoid bone), the pituitary gland is sometimes overlooked in routine postmortem examinations. Reported lesions in zoo animals include amyloidosis, adenomas, carcinomas, and pars intermedia dysfunction, as well as bacterial and fungal infections of the pituitary. With the recent advent of gonadotropin agonists (e.g., deslorelin) as a contraceptive for aggression control in some species, there is an additional need to carefully evaluate and archive the pituitary gland to fully understand the impact these treatments may have. In addition, estrogenic and other hormonally active environmental toxins have been associated with pituitary changes in wildlife species.

Removal of the pituitary gland can be achieved as a part of routine brain extraction using multiple different methods including removal of the skull cap, an off-center longitudinal section through the skull, or a transverse section through the skull and brain. After brain removal, the pituitary is generally retained in the sella turcica and can be elevated and extracted from the hypophyseal fossa. Routine fixation in 10% neutral buffered formalin is sufficient for most diagnostics; however, other fixatives such as ethanol, 4% paraformaldehyde, or gluteraldehyde may be needed for special studies. The pituitary gland should be a part of all routine zoo necropsies and can be archived in paraffin.