Pituitary Gland Disorders

Antidiuretic hormone or arginine vasopressin, is a peptide hormone released by the posterior pituitary in response to low plasma volume or increased plasma osmotic pressure. The hormone increases reabsorption of water at the kidney and increases systemic vascular resistance. When ADH is released in an unregulated fashion the circulating plasma becomes diluted, resulting in hyponatremia. This is called syndrome of inappropriate antidiuretic hormone secretion.

The pituitary gland, also known as hypophysis, is a small pea-sized gland about 1 cm in diameter and 0.5 to 1 gram in weight. The pituitary gland resides in a small bony cavity situated at the base of the brain, known as sella turcica, and a pituitary stalk (infundibulum) maintains a connection between the pituitary gland and hypothalamus. The secretion of hormones by the pituitary gland is under the influence of the hypothalamus through its various hormonal and neuronal signals. There are two distinct divisions of the pituitary gland: the posterior pituitary and the anterior pituitary. Between these two, there is a small zone, which is relatively avascular and less well-developed in humans, known as pars intermedia.

The pituitary gland also referred to as Hypophysis, or “Master gland” is a pea-sized organ, that lies in a protective bony enclosure called the sella turcica (saddle/chair) at the base of our brain. Read on to learn all about the pituitary gland and its hormones, as well as Hypopituitarism.

The hormone balance of the body is often organized in feedback control systems which adjust to the respective demands of the body. The most important example of such a system is the hypothalamus pituitary axis. In the following article, the interaction with the adrenal gland and the synthesis of glucocorticoids like cortisol serve as examples for the explanation of a complete hormonally regulated system. This is especially important in order to exactly classify and understand the genesis of some important endocrine diseases.

Excess production of growth hormone by pituitary gland in the body is given the name Acromegaly. The exact cause behind Acromegaly can be benign, noncancerous tumors formed in the pituitary gland. Middle aged adults are more prone to develop acromegaly. It is often diagnosed very late because of its slow and insidious onset. The symptoms varies from swelling of hands and feet to protruded lower jaws, joint pain, and deep voice. Accurate diagnosis is established by elevated level of growth hormone (GH) and Insulin-like Growth Factor I (IGF-1) in the blood.

The posterior pituitary secretes two hormones, oxytocin and vasopressin (anti-diuretic hormone). The word oxytocin literally means "quick birth" in Greek, which is an accurate description of the hormone's action. The following article discusses the positive and negative effects of oxytocin and vasopressin as well as their use as therapeutic options.

Patients with diabetes insipidus present with polyuria, urinary output > 3 L per day and can be central or nephrogenic in origin. In central diabetes insipidus, there is a decrease in the secretion of antidiuretic hormone (ADH), while in nephrogenic diabetes insipidus, the kidneys are unable to concentrate the urine due to ADH resistance.

The pituitary gland/hypophysis is in the Sella turcica/pituitary fossa which is a part of the sphenoid bone and forms the cranial fossa. The gland is divided into the posterior and the anterior pituitary. The most common cause of these disorders is pituitary tumors which are mostly benign (Adenomas) in nature. Diagnosis in most cases is made with MRI, CT imaging and laboratory work-ups. Treatment approaches for pituitary gland disorders involve various methods including medication and surgery. Prognosis depends on the diagnosis.

Hyperprolactinemia is defined as a condition of high prolactin levels in the blood. Many factors are attributed to the development of hyperprolactinemia. Bromocriptine or cabergoline are the first line of drugs for the treatment. Refractory cases require a surgery or radiation therapy in case hyperprolactinemia is caused by macroprolactinoma. This article discusses possible causes, diagnosis, treatment and management of hyperprolactinemia.