Figure 1: Anatomy of the rat’s pituitary gland and diagrams

Diagram 1: Indicates the different lobes of the pituitary gland	Inset: Shows the brain and location of the pituitary gland

The pituitary gland is located at the base of the brain and is protected by a bony structure called the sella turcica.
In in rats, as in other mammals, the pituitary gland is composed of the adenohypophysis and neurohypophysis. The adenohypophyis is represented by the anterior lobe (pars distalis), the intermediate lobe (pars intermedia) which is only rudimentary in humans, and the infundibulo-tuberal lobe (pars tuberalis). The neurohypophysis is composed of the posterior lobe (pars nervosa), the median eminence, and the hypophyseal stalk.

Control of the pituitary gland is under the influence of the hypothalamus. The secretion of hormones by the anterior lobe of the pituitary is regulated by releasing- hormones from the hypothalamus via the hypophyseal portal veins. Because there is no such portal vein connection in the neurohypophysis control by the hypothalamus is through nerve impulses.

Each lobe of the pituitary produces and secretes hormones that regulate many of the body’s functions, as well as to stimulate other endocrine glands. The hormones produced by the pituitary gland are not all secreted in continuous fashion. Many of the hormones are released in bursts, alternating between periods of activity and inactivity -(Merck Manual).

Staining techniques reflects three cell types in the anterior lobe categorized as: acidophils, basophils, and chromophobes. The addition of newer immunostaining techniques shows the specific hormones contained in those cell types, and in the lobes of the pituitary gland:

Anterior lobe (adenohypophysis or pars distalis)