The pituitary, the master gland of the body, produces eight different hormones that control or affect the rest of the endocrine system.



Pituitary Anatomy

The pituitary is a small bean-shaped organ about 1 cm in diameter. It is located at the base of the brain, just behind the chiasm of the optic nerves and cavernous sinuses. It sits in a bony structure called the sella turcica.

The pituitary is attached to the hypothalamus by the pituitary stalk.

The pituitary is composed of two distinct lobes - the anterior adenohypophysis (80%) and the posterior neurohypophysis.


Pituitary Control

The pituitary secretes its many hormones in a pulsatile fashion, with diurnal rhythm.

Positive feedback tends to come from the hypothalamus, while negative feedback comes from across hormonal pathways.


Hormones from the hypothalamus controlling the anterior pituitary are transported along neural axons and released in the infundibulum, where the hypothalmo-pituitary portal vessels reside. These vessels bathe the endocrine cells of the anterior pituitary.



Pituitary Hormones


The anterior pituitary produce six important hormones.

LH, FSH, and TSH all have alpha and beta subunits.


The Posterior Pituitary

Axons from the hypothalamus pass through the infundibulum to release hormones directly into blood vessels in th posterior pituitary. Two main hormones, oxytocin and anti-diuretic hormone, are released from the posterior pituitary after being synthesized as large propeptides, proteolytically cleaved, and released in its active form.


Pituitary Disease

Pituitary problems tend to fall in one of three categories: