The Aging process
The Aging process and changes in hormone production
The endocrine system consists of organs and tissues that produce hormones, natural chemicals produced in one location, secreted inside the bloodstream and then used by other target organs and systems.
The hormones control the target organs. Some organic systems have their own systems of internal control in place of hormones or with them.
As we age, natural changes occur in how body systems are controlled. Some target tissues become less sensitive to the hormone that controls and the amount of hormones produced may also change.
The blood levels of some hormones increase, some decrease, and some are unchanged. Hormones also decompose more slowly.
Many of the organs that produce hormones are in turn controlled by other hormones, but aging also causes changes in this process. For example, an endocrine tissue may produce less of the hormone than it did at a younger age or can produce the same amount, but at a slower rate.
AGING CHANGES
The hypothalamus is located in the brain and produces hormones that control other endocrine structures. The amount of these regulatory hormones remains almost the same, but the response from the endocrine organs may change as we age.
The pituitary gland is also located in the brain. This gland reaches its maximum size when people reach middle age and then gradually becomes smaller. It consists of 2 parts:
- The back portion, stores hormones produced in the hypothalamus.
- The front portion, produces hormones that affect the thyroid gland (TSH), adrenal cortex, ovaries, testicles and breasts.
The thyroid gland is located in the neck and produces hormones that help control the metabolism. With age, that gland may become lumpy. Metabolism decreases with time, starting around age 20. Because thyroid hormones are produced and broken down (metabolized) at the same rate, the thyroid function tests usually show results within the normal range.
The parathyroid glands are four small glands located near the thyroid. Parathyroid hormone affects levels of calcium and phosphate, which affects bone strength. The parathyroid hormone levels rise with age, which may contribute to osteoporosis.
The pancreas produces insulin, which helps sugar (glucose) to go from the blood to the cells, where it can be used as energy.
The average of glucose level (in fast) rises of 6-14 mg / dL (milligrams per deciliter) for every 10 years of life after age 50. This is because the cells become less sensitive to insulin effects.
The adrenal glands are located just above the kidneys. The adrenal cortex is the surface layer that produces the hormones cortisol and aldosterone.
- The aldosterone regulates fluid and electrolytes balance.
- Cortisol is the hormone of "stress response". It also affects the breakdown of glucose, proteins and fat, and has anti-inflammatory and antiallergic effects.
The aldosterone secretion decreases with age, which may cause dizziness and a decrease in blood pressure with sudden changes in position (orthostatic hypotension). Furthermore, the secretion of cortisol also decreases with age, but the level of this hormone in the blood remains almost the same. The DHEA levels also decline, although the effects of this drop in the body are not clear.
The ovaries and testes have two functions: produce reproductive cells (egg and sperm) and also produce sexual hormones that control secondary sex characteristics, such as breasts and facial hair.
- With age, men may experience a slight decrease in the level of detestosterona.
- Women have decreased levels of estradiol and other hormones, e.g., estrogen after menopause.
EFFECT OF CHANGES
Overall, some hormones decrease, some increase and others remain unchanged with age. Among those that usually fall are:
- Aldosterone.
- Calcitonin.
- Growth hormone.
- Renin.
In women, estrogen and prolactin levels usually decrease significantly.
The hormones that are unchanged or only slightly decreased include:
- Cortisol.
- Epinephrine.
- Insulin.
- Thyroid hormones T3 and T4.
Testosterone levels usually decrease slightly as men age.
Among the hormones that may increase we have:
- Follicle stimulating hormone (FSH).
- Luteinizing hormone (LH).
- Norepinephrine.
- Parathyroid hormone.
References:
Minaker KL. Common clinical sequelae of aging. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier, 2011: chap 24.
Updated: 2/9/2012
Version Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, ADAM Health Solutions, Ebix, Inc.
Translation and Localization by ADAM Logo
Taken from: http://www.nlm.nih.gov/medlineplus/spanish/ency/article/004000.htm