Pituitary Structure and Hormones

The pituitary gland has two parts – the anterior lobe and the posterior lobe that each has separate functions. The cells in the zone between these lobes are known as the intermediate pituitary which also has a distinct function.

The following hormones are produced and secreted by the Anterior Pituitary:

Thyroid Stimulating Hormone (TSH) causes the thyroid gland to produce and release thyroid hormones. Thyroid hormone controls the basal metabolic rate and plays an important role in growth and maturation. Thyroid hormones affect almost every organ in the body.

Growth Hormone (GH) regulates growth and metabolism.

Adrenocorticotropic Hormone (ACTH) triggers the adrenals to release the hormone cortisol, which regulates carbohydrate, fat, and protein metabolism and blood pressure. The adrenal glands sit above the kidneys and are also responsible for the body's fight or flight response.

Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH) control the production of sex hormones (estrogen and testosterone) and sperm and egg maturation and release.

Prolactin (PRL) stimulates production of breast milk and is necessary for normal milk production during breast feeding.

The following hormones are produced in the hypothalamus and stored and secreted by the Posterior Pituitary:

Anti-Diuretic Hormone (ADH) Also known as vasopressin controls water balance and blood pressure

Oxytocin – stimulates uterine contractions during labor and milk secretion during breastfeeding. It is thought to contribute to parent – newborn bonding known as attachment. Oxytocin is also thought to be involved in feelings of love and closeness, as well as in the sexual response.

Intermediate Pituitary

Melanocyte-Stimulating Hormone (MSH) regulates the production of melanin, a dark pigment, by melanocytes in the skin. Increased melanin production produces pigmentation or tanning of the skin; in certain conditions excessive production of melanocyte-stimulating hormone can cause darkening of the skin.