Located at the base of the brain, the pituitary gland secretes hormones which enter the bloodstream, and govern the functions of other endocrine glands in the body, and thus it is also referred to as the "master gland". The functionality of this gland comprises the working of its two sections: the anterior pituitary, and the posterior pituitary.
The anterior section is the front and bigger part, and is responsible for releasing most of the hormones. The posterior section is the back portion. It is smaller and does not produce its own hormones, but stores those secreted by the hypothalamus.
One of the important functions of the hypothalamus is to control the pituitary gland. In short, a coalition of the hypothalamus and the pituitary gland, controls other endocrine glands, and many other functions in the body.
The Working of the Pituitary Gland
The Anterior Pituitary
Also known as adenohypophysis, the anterior pituitary performs following functions:
► It secretes the adrenocorticotropic hormone (ACTH), which is required for stimulating the adrenal cortex to produce cortisol. Cortisol is vital for processes which include immune function, metabolism, stress management, regulation of blood sugar levels, controlling blood pressure, and anti-inflammatory responses.
► It releases the thyroid-stimulating hormone (TSH). As the name suggests, this hormone stimulates the thyroid gland to make its own hormones, which are important for controlling the metabolic rate of the body. These thyroid hormones include triiodothyronine (T3) and thyroxine (T4).
► It secretes the growth hormone (GH) for stimulating growth and cell reproduction, and regeneration in humans and other animals.
► It secretes prolactin. This hormone is essential for making breast milk during pregnancy and after childbirth. The release of this hormone into the bloodstream depends on the demand for breast milk. When a woman is breastfeeding, her prolactin level will remain high.
In mothers, who do not breastfeed after childbirth, prolactin levels return to normal. Prolactin is also present in men and nonpregnant women, but in small quantities.
► It releases the follicle-stimulating hormone (FSH). In women, this hormone plays the role of maturing the eggs released during ovulation. In men, it regulates sperm production.
► It releases the hormone called luteinizing hormone (LH). In women, once an egg is matured, its release from the ovary is triggered by the LH. In men, this hormone controls the production of testosterone, which is required for the production of sperm.
Note: In several animals, between the anterior and posterior pituitary, there exists what is known as the intermediate lobe. It is also present in humans, but only as a layer of cells between the two sections; in fact, it is attributed as but a part of the anterior pituitary. This intermediate section is known to produce melanocyte-stimulating hormone (MSH).
Although the role of this hormone in humans is not specifically known, it is believed to trigger hyperpigmentation, if released in higher amounts.
The Posterior Pituitary
Also known as neurohypophysis, the posterior pituitary functions as a mere reservoir of hormones secreted by the hypothalamus, which include the antidiuretic hormone (ADH) and oxytocin.
► The antidiuretic hormone (ADH) is called so because it inhibits the production of dilute urine in the body. Also known as vasopressin, this hormone is released by the hypothalamus, when it detects too little water in blood. Once the hormone is released, the kidneys react by reabsorbing more water and producing more concentrated urine (less diluted urine).
In this way, it helps stabilizing the blood water level. ADH is also responsible for increasing blood pressure.
► Oxytocin is a hormone that plays a vital role in childbirth. It triggers uterine contractions during and after labor, thus encouraging rapid delivery. The same hormone also stimulates the ejection of breast milk, as a response to the sight, sound or suckling of a newborn.
Oxytocin is also known as the "love hormone", for it gets released into the bloodstream during orgasms in both men and women. In men particularly, the hormone helps maintain erections. Recent findings show that, the hormone may be associated with improving emotions such as trust, empathy, and reducing anxiety and stress.
In people with autism, a few studies purport that oxytocin may help with social functioning. To add to this, a study conducted at Claremont Graduate University in Claremont, California, showed that, in women, this hormone may boost happiness.
A common disorder of the pituitary gland is the formation of tumors in it. The cells of the gland may malfunction and grow rapidly or may produce small growths and lead to the formation of tumors. Such tumors are, however, not brain tumors and are non-cancerous.
These tumors may be of two types; secretory and non-secretory. The former type produces too much hormones, and the latter type keeps the pituitary gland from functioning optimally.
Disclaimer: The information provided is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.