The pituitary gland is a pea-sized endocrine gland located in the brain. It releases a number of hormones that are needed for many functions that go on in the body. Pituitary hormones are essential for growth, development, reproduction and proper functioning of some other endocrine--hormone secreting--glands. One of the hormones secreted by the pituitary gland is adrenocorticotropic hormone, or ACTH.
The Adrenal Glands
The adrenal glands are located above the kidneys and secrete several classes hormones. The adrenal gland has two parts--the adrenal medulla and the adrenal cortex. The adrenal medulla secretes catecholamines, while the adrenal cortex secretes sex hormones, mineralocorticoids and glucocorticoids. Catecholamines such as epinephrine help get the body ready for physical activity, while mineralocorticoids such as aldosterone regulate fluid and salt balance in the body. Cortisol is a glucocorticoid that regulates blood pressure and blood glucose levels and helps the body cope with stress like surgery and infection. When the adrenal gland makes too much or too little cortisol, a hormonal disorder occurs.
ACTH Effects
The pituitary gland controls the function of the adrenal cortex. When it secretes ACTH, it stimulates the adrenal glands to produce cortisol. A tumor in the pituitary gland may cause it to overproduce or underproduce ACTH. Abnormal production of ACTH can then make the adrenal glands secrete too much or too little cortisol and some other hormones of the adrenal cortex. Too much ACTH leads to high levels of cortisol in the body, and this causes Cushing's disease. Too little ACTH results in low cortisol production and a condition called secondary adrenal insufficiency.
Overactive Pituitary Gland
When the pituitary gland secretes too much ACTH in the presence of a tumor, Cushing's disease occurs. In this disease, the body is exposed to abnormally high levels of cortisol. Some symptoms of this problem are a humped back, a round face-- also called a moon face, increase in weight around the abdomen, high blood pressure, high blood sugar levels, fragile bones or osteoporosis and thin easily bruised skin.
Underactive Pituitary Gland
A pituitary tumor can inhibit ACTH production in the pituitary gland. When this happens, the adrenal glands do not produce enough cortisol and this leads to secondary adrenal insufficiency--a condition where cortisol production is low due to low ACTH secretion by the pituitary gland. "The Philadelphia Guide: Inpatient Pediatrics" by Gary Frank, Samir S. Shah, Marina Catallozzi and Lisa B. Zaoutis says signs and symptoms of this problem are weakness, fatigue, loss of appetite, weight loss, nausea, vomiting, diarrhea, dizziness, low blood volume and fast heart beats.
Treatment
A pituitary tumor can be treated with surgical removal of the tumor. Radiation can also be used to destroy pituitary tumors. The Hormone Foundation reports that hormone replacement therapy may be needed in cases where the pituitary tumor causes a hormonal deficiency. Secondary adrenal insufficiency can be treated with hormone replacement therapy.
References
- Merck Manuals Online Medical Library: Pituitary Gland Disorders
- The Hormone Foundation: Pituitary Disorders Treatment Options
- "The Philadelphia Guide: Inpatient Pediatrics" Gary Frank, Samir S. Shah, Marina Catallozzi and Lisa B. Zaoutis; 2005
- Merck Manuals Online Medical Library: Adrenal Gland Disorders
