The pituitary gland or hypophysis is a small gland about 1 centimeter in diameter or the size of a pea. It is nearly surrounded by bone as it rests in the sella turcica, a depression in the sphenoid bone. The gland is connected to the hypothalamus of the brain by a slender stalk called the infundibulum.

There are two distinct regions in the gland: the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis). The activity of the adenohypophysis is controlled by releasing hormones from the hypothalamus. The neurohypophysis is controlled by nerve stimulation.

Hormones of the Anterior Lobe (Adenohypophysis)

Growth hormone (GH) is a protein that stimulates the growth of bones, muscles, and other organs by promoting protein synthesis. This hormone drastically affects the appearance of an individual because it influences height. If there is too little growth hormone in a child, that person may become a pituitary dwarf of normal proportions but small stature. An excess of the hormone in a child results in an exaggerated bone growth, and the individual becomes exceptionally tall or a giant.

The study of GH includes GH with clonidine stimulation and IGF1. For confirmation of GH deficiency two test like one stimulation and one growth factor test is required. Our laboratory is the pioneer in doing both these tests by RIA and/or ELISA.

While study of GH excess is carried out by the study of Basal and post Glucose GH levels at 60 min. This can confirm the diagnosis of Acromegaly.

Thyroid-stimulating hormone, or thyrotropin, (TSH) causes the glandular cells of the thyroid to secrete thyroid hormone. When there is a hypersecretion of thyroid-stimulating hormone, the thyroid gland enlarges but do not produce enough thyroid hormones. This condition is called as Hypothyroidism.. When there is hyposecretion of the TSH, it will cause hypersecretion of the thyroid hormones from the thyroid gland due to absene or poor negative feedback. This will result in Hyperthyroidism.

Adrenocorticotropic hormone (ACTH) reacts with receptor sites in the cortex of the adrenal gland to stimulate the secretion of cortical hormones, particularly cortisol. In suspected patients with Cushings or Addisons disease study of Cortisol or ACTH and Synacthen stimulation provide confirmative diagnosis.

Gonadotropic hormones react with receptor sites in the gonads, or ovaries and testes, to regulate the development, growth, and function of these organs. Study of Goandotropic hormones like FSH, LH are important for infertility in male and female.

Prolactin hormone promotes the development of glandular tissue in the female breast during pregnancy and stimulates milk production after the birth of the infant. Study of prolactin secretion in blood provides an important clue for infertility in females and libido in males.

Hormones of the Posterior Lobe (Neurohypophysis)

Antidiuretic hormone promotes the reabsorption of water by the kidney tubules, with the result that less water is lost as urine. This mechanism conserves water for the body. Insufficient amounts of antidiuretic hormone cause excessive water loss in the urine. ADH study is an important marker for Diabetes insipidus and those operated for pituitary surgery.

Oxytocin causes contraction of the smooth muscle in the wall of the uterus. It also stimulates the ejection of milk from the lactating breast.