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Showing posts with label hormone. Show all posts
Showing posts with label hormone. Show all posts

Wednesday, July 10, 2013

Hormone Effective for Steroid-Induced Osteoporosis

The synthetic parathyroid hormone teriparatide is an effective treatment for glucocorticoid-induced osteoporosis, a form of bone loss seen in patients treated with steroids, according to a study funded by the manufacturer.

Patients with glucocorticoid-induced osteoporosis who took teriparatide for 36 months had greater increases in bone mineral density and fewer vertebral fractures than those treated with alendronate, a bisphosphonate osteoporosis drug sold as Fosamax, an online article in Arthritis & Rheumatism reported.

Subjects at high risk of fracture associated with sustained glucocorticoid use who received teriparatide had significantly greater increases in spine and hip BMD compared with subjects receiving alendronate during the 36 months of therapy.

Patients with glucocorticoid-induced osteoporosis treated with teriparatide also experienced significantly fewer new vertebral fractures, most occurring during the first 18 months, with no significant difference between groups in the incidence of nonvertebral fractures."

Glucocorticoids are used to control inflammation in patients with autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, and Crohn's disease, as well as inflammatory conditions such as asthma.

However, long-term use of glucocorticoids such as prednisone, prednisolone, dexamethasone, and cortisone can result in reduced bone mass and strength, increasing fracture risk.

In the new study, participants were randomly assigned to receive injectable teriparatide (20 µg/day) plus oral placebo (150 subjects) or oral alendronate (10 mg/day) plus injectable placebo (144 subjects). They were also given supplements of calcium and vitamin D.

In addition to seeing greater improvements in bone mineral density and fewer vertebral fractures, subjects who took teriparatide saw significant increases in levels of biomarkers of bone turnover, including N-terminal type I procollagen propeptide (PINP), osteocalcin (OC) and C-terminal telopeptide of type I collagen (CTX).

More patients who took teriparatide (21%) had elevated predose serum calcium concentrations compared with those in the alendronate group (7%)"Our data indicated that teriparatide is efficacious and generally well tolerated for treating subjects with glucocorticoid-induced [osteoporosis] and should be considered as a therapeutic option for subjects at high risk of fracture," the authors concluded.

They noted that the study had a high dropout rate, with 44% of patients leaving during the three years, which might have reflected the severity of the disorders being treated and the propensity for the patients to have other diseases. However, there was no difference in dropout rates between the two study groups.

Friday, May 10, 2013

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, released into the bloodstream, then used by other target organs and systems.

The hormones control the target organs. Some organ systems have their own internal control systems along with, or instead of, hormones.

As we age, 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 may also 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 at a younger age, or it may produce the same amount at a slower rate.

AGING CHANGES

The hypothalamus is located in the brain. It produces hormones that control the other structures in the endocrine system. The amount of these regulating hormones stays about the same, but the response by the endocrine organs can change as we age.

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 back (posterior) portion stores hormones produced in the hypothalamus.
    The front (anterior) portion produces hormones that affect the thyroid gland (TSH), adrenal cortex, ovaries, testes, and breasts.

The thyroid gland is located in the neck. It produces hormones that help control metabolism. With aging, the thyroid may become lumpy (nodular). Metabolism slows over time, beginning at around age 20. Because thyroid hormones are produced and broken down (metabolized) at the same rate, thyroid function tests usually show results within the normal range.

The parathyroid glands are four tiny glands located around the thyroid. Parathyroid hormone affects calcium and phosphate levels, which affect the strength of the bones. Parathyroid hormone levels rise with age, which may contribute to osteoporosis.

Insulin is produced by the pancreas. It helps sugar (glucose) go from the blood to the inside of cells, where it can be used for energy.

The 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.

The adrenal glands are located just above the kidneys. The adrenal cortex, the surface layer, produces the hormones aldosterone and cortisol.

    Aldosterone regulates fluid and electrolyte balance.
    Cortisol is the "stress response" hormone. It affects the breakdown of glucose, protein, and fat, and has anti-inflammatory and anti-allergy effects.

Aldosterone release decreases with age, which can contribute to light-headedness and a drop in blood pressure with sudden position changes (orthostatic hypotension). Cortisol release also decreases with aging, but the blood level of this hormone stays about the same. Dehydroepiandrosterone levels also drop, although the effects of this drop on the body are not clear.

The ovaries and testes have two functions. They produce the reproductive cells (ova and sperm). They also produce the sex hormones that control secondary sex characteristics, such as breasts and facial hair.

    With aging, men sometimes experience a slightly decreased level of testosterone.
    Women have decreased levels of estradiol and other estrogen hormones after menopause.

EFFECT OF CHANGES

Overall, some hormones are decreased, some unchanged, and some increased with age. Hormones that are usually decreased include:

    Aldosterone
    Calcitonin
    Growth hormone
    Renin

In women, estrogen and prolactin levels usually decrease significantly.

Hormones that remain unchanged or only slightly decreased include:

    Cortisol
    Epinephrine
    Insulin
    Thyroid hormones T3 and T4

Testosterone levels usually decrease slightly as men age.

Hormones that may increase include:

    Follicle-stimulating hormone (FSH)
    Luteinizing hormone (LH)
    Norepinephrine
    Parathyroid hormone