Acromegaly is caused by the uncontrolled hypersecretion of growth hormone (GH)
by the pituitary, a tiny gland — about the size of a pea –– located just below your brain, behind your eyes. The pituitary is also known as the "master gland" – this is because
it controls multiple functions, including normal growth, metabolism, and reproductive activity. In most cases, the cause of this excessive production of GH is a noncancerous tumor on the pituitary. This pituitary tumor secretes a high level of GH, causing the enlargement of many body parts, such as the hands and feet. Because of where it
is located, this tumor can also cause headaches with pressure behind the eyes.
Understanding the Causes of Acromegaly
There are 3 important hormones that circulate throughout your body that regulate many of the most basic activities of your body. These hormones play a key role in acromegaly:
Growth Hormone (GH) - The pituitary releases GH in short spurts throughout the day and night, resulting in constantly varying GH levels. When a person has acromegaly, abnormally high levels of GH are released by the pituitary.
Too much GH causes changes in physical characteristics and other aspects of your body.
Insulin-like Growth Factor-1 (IGF-1) - IGF-1 levels rise whenever GH levels rise;
however, IGF-1 (made mostly in the liver) is released more evenly than GH, and IGF-1 levels remain higher longer. When both of these levels are elevated together, they can also cause many of the signs and symptoms of acromegaly.
Somatostatin - One of the main effects of somatostatin is its ability to control the amount of GH in the body. Researchers have taken advantage of this knowledge in developing treatments for acromegaly. Natural somatostatin is broken down by the
body in a matter of minutes, whereas treatments based on somatostatin remain active much longer.
GH is produced by the pituitary. IGF-1 is produced primarily by the liver in response to GH. Somatostatin is produced by the hypothalamus, a part of the brain that influences the pituitary.
