For example, a low supply of growth hormone slows the growth of a child. Dwarfism or other problems can result. A head injury may stop the gland from working. When the blood supply is cut off by a growing tumor or aneurysm, the gland may not be able to function. Decreased hormone production from the pituitary gland may result from radiation therapy used to treat a tumor.
Pituitary tumors are usually benign or noncancerous.
One type of tumor reduces the production of specific sex hormones. This can lead to a failure of sexual function. Monthly periods may stop in women and the amount of sperm may be reduced in men. Another type of tumor causes an excess of hormones. Rapid growth before adulthood may occur.