Hormone Testing at Access Medical Laboratories

HORMONE INFORMATION - MELATONIN

What is it?

Melatonin is a hormone secreted by the pineal gland in the brain that helps regulate other hormones and maintains the body's circadian rhythm. The circadian rhythm is an internal 24-hour time-keeping system that plays a critical role in determining when we fall asleep and when we wake up. Darkness stimulates the production of melatonin while light suppresses its activity. Exposure to excessive light in the evening or too little light during the day can disrupt the body's normal melatonin cycles. For example, jet lag, shift work, and poor vision can disrupt melatonin cycles. In addition, some experts claim that exposure to low-frequency electromagnetic fields (common in household appliances) may disrupt normal cycles and production of melatonin.

Melatonin also helps control the timing and release of female reproductive hormones. It helps determine when menstruation begins, the frequency and duration of menstrual cycles, and when menstruation ends (menopause).

Many researchers also believe that melatonin levels are related to the aging process. For example, young children have the highest levels of nighttime melatonin. Researchers believe these levels diminish as we age. In fact, the decline in melatonin may explain why many older adults have disrupted sleep patterns and tend to go to bed and wake up earlier than when they were younger. However, emerging research calls this theory into question.

In addition to its hormonal actions, melatonin has strong antioxidant effects. Preliminary evidence suggests that it may help strengthen the immune system.

RESOURCES:

1. a b c Altun A, Ugur-Altun B (2007). "Melatonin: therapeutic and clinical utilization". Int. J. Clin. Pract. 61 (5): 835­45. doi:10.1111/j.1742-1241.2006.01191.x. PMID 17298593.

2. Boutin J, Audinot V, Ferry G, Delagrange P (2005). "Molecular tools to study melatonin pathways and actions". Trends Pharmacol Sci 26 (8): 412­9. doi:10.1016/j.tips.2005.06.006. PMID 15992934.

3. a b Hardeland R (2005). "Antioxidative protection by melatonin: multiplicity of mechanisms from radical detoxification to radical avoidance". Endocrine 27 (2): 119­30. doi:10.1385/ENDO:27:2:119. PMID 16217125.