What is the pituitary gland and where is it located?

The pituitary is a small gland (no larger than a pea) located at the base of the brain near the optic nerves. It rests in a saddle-like compartment in the skull called the “sella turcica”. The pituitary gland plays a key role as the master gland of the endocrine system. It receives information from the brain via the hypothalamus and produces hormones that are important to the functioning of other organs. These hormones are released in the blood circulation in order to reach their target organs.

The pituitary is composed of two lobes: the posterior lobe and the anterior lobe (called adenohypophysis) containing the five hormone-secreting cell types. The pituitary posterior lobe stores two hormones produced by the hypothalamus: antidiuretic hormone (ADH) important for water reabsorption and oxytocin important for uterine contractions. The pituitary anterior lobe is comprised of five different cells, each producing a corresponding hormone.

 

    • One cell type (corticotrophs) produces adrenocorticotropin (ACTH) that stimulates the release of glucocorticoid by adrenals, contributing to normal blood pressure and electrolyte balance.

    • The second cell type (thyrotrophs) produces thyroid-stimulated hormone (TSH) that stimulates thyroid hormone release by the thyroid gland, contributing to metabolism.

    • The third type (gonadotrophs) secretes gonadotrophins (LH and FSH) that regulate sexual function and reproduction.

    • The fourth type (lactotrophs) produce prolactin, the hormone of lactation.

  • Finally, the somatotrophs produce GH that stimulates the production of insulin growth factor 1 (IGH-1) by the liver, regulating the growth.

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