The adrenal gland is part of a complex network of organs that form the endocrine system. Like the nervous system, the endocrine system regulates communication between the various organs of the body. Unlike the nervous system, the endocrine system uses chemicals called hormones, rather than nerve impulses, as the mechanism by which information is shared. When the adrenal glands are overactive, the hormones they produce can reach excessive levels and cause miscommunication that destroys the body's normal homeostasis.
Pituitary Gland Dysfunction
The pituitary gland, located deep within the brain, is smaller than a marble but wields powerful control over numerous aspects of human physiology. Hormones secreted by the pituitary gland act in regulating metabolism, ovulation, blood pressure, growth and a host of other biological functions.
The University of Maryland Medical Center states that a hormone released by the anterior lobe of the pituitary gland, called adrenocorticotropic hormone, or ACTH, directly stimulates the adrenal gland. When ACTH is secreted in excessive amounts, it can prompt overactivity of the adrenal gland. Tumors are a factor that can cause hypersecretion of hormones by the pituitary gland, resulting in overactivity of the adrenal gland.
Hypothalamic Dysfunction
The hypothalamus is a small endocrine gland that is located in the diencephalon, an area of the brain. Gary Thibodeau, Ph.D., author of "The Human Body in Health and Disease," explains that this small gland is one of the most important structures in the brain.
The hypothalamus exerts influence over the pituitary gland via two different mechanisms. It produces chemicals called releasing hormones that enter the blood and travel to the pituitary gland, where they influence the release of pituitary hormones. The hypothalamus also produces hormones that the pituitary gland secretes.
Through its influence over pituitary gland function, the hypothalamus indirectly controls the activity of the adrenal glands as well. A dysfunction that causes the hypothalamus to oversecrete releasing hormone can subsequently cause the pituitary gland to produce an excessive amount of ACTH, which overstimulates the adrenal glands.
Primary Adrenal Dysfunction
Disorders originating in the hypothalamus or pituitary gland that cause adrenal dysfunction are referred to as secondary adrenal disorders. Primary adrenal disorders, such primary adrenal hyperplasia, originate within the adrenal gland itself.
Primary adrenal hyperplasia is a genetic disorder that results in overproduction of androgens, which are male hormones that are present in both men and women. Excessive amounts of androgens can cause women to develop masculine characteristics such as facial hair and deep voices, according to the University of Maryland Medical Center.
