The endocrine system consists of a group of glands and organs that regulate and control various body functions by producing and secreting hormones. Hormones are chemical substances that affect the activity of another part of the body. In essence, hormones serve as messengers, controlling and coordinating activities throughout the body.
Endocrine disorders involve either
Too much hormone secretion (called "hyper" function)
Too little hormone secretion (called "hypo" function)
Disorders may result from a problem in the gland itself, or because the hypothalamic-pituitary axis (interplay of hormonal signals between the hypothalamus, and the pituitary gland) provides too much or too little stimulation. Depending on the type of cell they originate in, tumors can produce excess hormones or destroy normal glandular tissue, decreasing hormone production. Sometimes the body's immune system attacks an endocrine gland (an autoimmune disorder), decreasing hormone production.
Examples of endocrine disorders include
Disorders of puberty and reproductive function
Doctors usually measure levels of hormones in the blood or urine to tell how an endocrine gland is functioning. Sometimes blood levels alone do not give enough information about endocrine gland function, so doctors measure hormone levels:
At certain times of the day or more than once or at different times of the day (such as cortisol)
After giving a stimulus or suppressor (such as a sugar-containing drink, a drug, or a hormone that can trigger or block hormone release)
After having the person take an action (such as fasting)
Endocrine disorders are often treated by replacing a hormone that is deficient or decreasing levels of a hormone that are excessive. However, sometimes the cause of the disorder can be treated. For example, a tumor involving an endocrine gland may be removed.
(See also Endocrine Glands.)
