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All mammals have a “biological clock” which generates and regulates the circadian rhythms.  This biological clock is located within the suprachiastmatic nucleus (SCN) in the hypothalamus in the brain.  The SCN is  a tiny, slightly cone shaped region composed of several different types of cells.  It is just the size of a grain of rice, located in the front part of the hypothalamus just above the optic chiasm (where the optic nerves come together before separating again into the optic tracts) which may explain its reactivity towards light.  Despite its tiny size, the SCN has a powerful effect on our bodies, controlling when we awaken, when we sleep and when we are able to reproduce.  There is some evidence to suggest that it may even control our sexual orientation.  A larger SCN has been found in homosexual men when compared with heterosexual men in several early studies.  

One of the best known hormones involved in regulating the circadian rhythm is melatonin.  Melatonin is a powerful antioxidant as well as being involved in regulating our body clock or circadian rhythms and reproductive function.  It has been studied for the treatment of cancer, cardiovascular diseases, circadian rhythm sleep disorders, depression, immune disorders, seasonal affective disorder (SAD) and sexual dysfunction and may strengthen the immune system and have anti-aging potential.  Melatonin is produced by the pineal gland in the brain when you are asleep and is produced most efficiently under conditions of complete darkness.  Melatonin helps you to fall asleep and stay asleep throughout the night, but exposure to light can stop the pineal gland from producing enough melatonin.

The invention of electricity has changed the world without question.  It has enabled humans to stay up late into the night, watching television, surfing the internet, reading books, and even writing articles when they should be tucked up in bed fast asleep.

If you have difficulty falling asleep, or awakening in the morning it is recommended that you:

  • Reduce your exposure to stimulating things like bright lights, television and computers for 2 hours before you intend to go to bed
  • Get into a routine of going to bed at the same time each night.  Ideally that time should be no later than 10pm
  • Ensure your bedroom is pitch black at night
  • If you need to get up throughout the night, minimise your exposure to bright lights
  • Get up at the same time each morning.  Ideally that time should be 6am.
  • Go outside or turn the lights on when you wake, so that your body knows to reduce the production of melatonin and increase the production of serotonin.

Whilst managing your melatonin/serotonin balance through natural means like the above is the best solution, sometimes due to the pressures and demands of our lives we somehow don’t manage to fit everything in and still get to bed by 10pm.  In these instances it may be worth considering supplementing with melatonin as an interim measure to help restore circadian rhythms or as a sleep aid.

A recent paper published in the Journal of Pineal Research has found that supplementation with the 5mg of the hormone melatonin 2 hours before bed for 2 months can have a positive effect on some symptoms and biomarkers of metabolic syndrome. Metabolic syndrome is closely related in its pathophysiology to polycystic ovarian syndrome, in fact many women with PCOS progress to having metabolic syndrome as well, so this research is of great interest to us.  Many women with PCOS also have a disordered biological clock and suffer from insomnia and lethargy.  It is possible that restoring the circadian rhythms to their normal pattern may reduce insulin resistance and ameliorate the symptoms of metabolic syndrome.  Excessive exposure to lights in the evenings before bed and insufficient exposure to bright light in the morning on awakening and throughout the day can impair the balance between melatonin and serotonin, affecting our natural inclination to sleep at night and to be active and energetic during the day.  This can affect the reproductive cycle, causing disordered ovarian function, irregularity of menstrual cyclicity, increased symptoms associated with the menstrual cycle and infertility.  Women with PCOS seem to be more vulnerable to hormonal disruption from inappropriate exposure to light/darkness.

PCOS is fundamentally a result of disordered hormone balance within the body.  In fact, some scientists have hypothesized that PCOS is an ovarian manifestation of metabolic syndrome.  Hormone production is a very complicated affair, with many glands involved and many opportunities for imbalance.  Commonly affected hormones that have been identified as being involved in PCOS to date include oestrogen, progesterone, prolactin, luteinising hormone (LH), testosterone, androstenedione, dehydroepiandosterone (DHEA), sex hormone binding globulin (SHBG), insulin, leptin, ghrelin & cortisol.

What is a Hormone?

A hormone is a chemical substance produced by one cell or organ in the body which has an effect on another cell or organ, usually to regulate a process, by either speeding it up or slowing it down, making more or less of  of something.  Most hormones are produced by glands, although there are some exceptions, such as cholecalciferol or Vitamin D which is produced by the skin.    Many hormones use cholesterol as their building material, including the hormones involved in PCOS – the steroidogenic hormones.  Some other substances which the body can use to build hormones are amino acids, fatty acids or proteins.

Melatonin plays an essential role in the reproductive cycle and has a direct effect on the function of the ovaries.  It is responsible for when a woman begins and ceases menstruating (menarche and menopause), and for the duration and frequency of her periods (menstruation).  It is found in significant quantities within ovarian follicular fluid and there are melatonin receptors in the ovaries.  Melatonin levels at night are highest in children.  As we age, we produce less of this valuable antioxidant hormone.

More Information:

Kozirog M et al, Melatonin treatment improves blood pressure, lipid profile, and parameters of oxidative stress in patients with metabolic syndrome, J Pineal Res, 2010, Dec 8

Acuna-Castroviejo D, Escames G, Rodriguez MI, Lopez LC. Melatonin role in the mitochondrial function. Front Biosci. 2007;12:947-63.

Allen LS, Gorski RA (1992). “Sexual orientation and the size of the anterior commissure in the human brain”. Proc. Natl. Acad. Sci. U.S.A. 89 (15): 7199–202.

Altun A, Ugur-Altun B. Melatonin: therapeutic and clinical utilization. Int J Clin Pract. 2007;61(5):835-45.

Arendt J. Melatonin, circadian rhythms and sleep. New Engl J Med; 2000;343(15):1114-1116.

Attele AS, Xie JT, Yuan CS. Treatment of insomnia: an alternative approach.Altern Med Rev. 2000;5(3):249-259.

Cornelissen G, Halberg F, Burioka N, Perfetto F, Tarquini R, Bakken EE. Do plasma melatonin concentrations decline with age? Am J Med. 2000;109(4):343-345.

la Fleur SE, Kalsbeek A, Wortel J, van der Vliet J, Buijs RM. Role for the Pineal and Melatonin in Glucose Homeostasis: Pinealectomy Increases Night-Time Glucose Concentrations. J Neuroendocrinology; 2001; 13, 1025-1032

Lewy AJ, Emens J, Jackman A, Yuhas K. Circadian uses of melatonin in humans. Chronobiol Int. 2006;23(1-2):403-12.

Malhotra S, Sawhney G, Pandhi P. The therapeutic potential of melatonin: a review of the science. Medscape General Medicine 2004;6(2).

Nagtagaal JE, Laurant MW, Kerkhof GA, Smits MG, van der Meer YG, Coenen AM. Effects of melatonin on the quality of life in patients with delayed sleep phase syndrome. J Psychosom Res. 2000;48(1):45-50.

Piccirillo JF. Melatonin. Prog Brain Res. 2007;166:331-3.

Reiter RJ. Melatonin: clinical relevance. Best Pract Res Clin Endocrinol Metab. 2003;17(2):273-85.

Swaab DF, Hofman MA (1990). “An enlarged suprachiasmatic nucleus in homosexual men”.Brain Res. 537 (1–2): 141–8.

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