Please be patient! It may take up to ONE minute to load all the Engines.
Problems? Please contact our support.
Aging changes in hormone production
The endocrine system is made up of organs and tissues that produce hormones. Hormones are natural chemicals produced in one location, secreted into the bloodstream and then used by certain other "target" organs and system.
The hormones control the target organs. Some organ systems have their own internal control systems instead of, or in addition to, hormones.
With aging, changes naturally occur in the way that body systems are controlled. Some target tissues become less sensitive to their controlling hormone. The amount of hormones produced can change.
Blood levels of some hormones increase, some decrease, and some are unchanged. Hormones are also broken down (metabolized) more slowly.
Many of the organs that produce hormones are, in turn, controlled by other hormones. Aging also changes this process. For example, an endocrine tissue may produce less of its hormone than it did when you were younger, or it may produce the same amount at a slower rate.
For example, a hormone called TRH makes the pituitary gland produce thyrotropin , or thyroid stimulating hormone ( TSH ). In women, the amount of TSH produced does not decrease with time, but it does in men.
The pituitary gland is also located in the brain. This gland reaches its maximum size in middle age and then gradually becomes smaller. It has two parts:
The thyroid gland is located in the neck and produces hormones that help control metabolism . With aging, the thyroid often becomes lumpy (nodular). Metabolism gradually declines, beginning about age 20.
Less thyroid hormone may be produced, but there is also less body mass (because of loss of muscle and bone tissue) so thyroid function tests usually remain within the normal range.
The parathyroids are four tiny glands located around the thyroid. Parathyroid hormone affects calcium and phosphate levels. This, in turn, affects the strength of the bones. Changes in the level of parathyroid hormones may contribute to osteoporosis .
The normal or average fasting glucose level rises 6 to 14 mg/dL (milligrams per deciliter) for each 10 years after age 50. This is because the cells become less sensitive to the effects of insulin (probably because of a loss in the number of insulin receptor sites in the cell wall).
Because of these changes, older people periodically should have blood drawn to check glucose levels and make sure they aren't in the early stages of diabetes, or high blood sugar.
The adrenal glands are located just above the kidneys. The adrenal cortex, the surface layer, produces the hormones aldosterone and cortisol.
Aldosterone secretion decreases with age, which can contribute to light-headedness and a drop in blood pressure with sudden position changes (orthostatic hypotension ). Cortisol secretion decreases, but the level stays about the same.
The ovaries and testes have two functions. They produce the reproductive cells (ova and sperm). They also produce the sex hormones (those that control secondary sex characteristics, such as breasts and facial hair).
EFFECT OF CHANGES
In women, estrogen and prolactin levels usually decrease.
Hormones that remain unchanged or only slightly decreased include:
Testosterone levels usually decrease slightly as men age.
Hormones that may increase include:
Update Date: 11/1/2002Steven Angelo, M.D., Assistant Professor of Medicine, Yale School of Medicine, New Haven, CT. Review provided by VeriMed Healthcare Network.
Last updated: Tue, 06 Jan 2009 00:20:03 GMT