Melatonin

 

Melatonin is a hormone produced by the pineal gland. It secretes melatonin in a circadian fashion. It has an in built rhythm of about 24.5-25.5 hours. Levels start to rise at around 8.00 p.m. and are maximal at 2-3.00 a.m. and fall by 8.00 a.m. It is the main internal timegiver to the body and is the key neuroendocrine modulator of annual and Circadian biorythms in man. The intrinsic rhythm can be altered by external clues such as the light/dark cycle, social clues such as an alarm clock going off or having to go to work and also therapeutically by light therapies and can be interfered with by various pharmaceutical agents. The commonest are beta blockers which block the beta receptors of the pineal gland inhibiting melatonin synthesis producing insomnia and non-steroidal anti-inflammatories which can inhibit melatonin synthesis also.
Rhythms are important to the body as they control chaos. Integration of the endocrine, immune and nervous systems are very important for communication, co­ordination and control over the body's processes. Rhythmic changes in hormone levels are the main way stability is ensured in the body. Clinically, problems can arise with various situations. The commonest encountered are those concerning the effects of jet lag and shift work. However, melatonin abnormalities have been demonstrated in the so called seasonal affective disorder which is where people have high levels of winter time melatonin accompanied by carbohydrate craving. More recently abnormalities have been found in people suffering from CFS (ME) and may be one of the reasons their illness is prolonged. Biologically its actions are:
1. Sleep induction via the histamine interleukin prostaglandin pathway.
2. Buffering of stress hormones such as cortisol.
3. Immune system conditioning.
4. Anti-oxidant effects, being the body's most powerful natural anti-oxidant.
5. Potentiation of other hormones, e.g. T4 to T3 conversion is enhanced by melatonin.
6. Inhibition of gonadotrophin hormones.

There is an interesting group of patients who often present with multiple food allergies/sensitivities. A common symptom patients have is feeling bloated after food.

They can be shown on occasions to have high levels of melatonin released from the gastrointestinal tract after eating — this can be treated with anti-histamines. All treatments should last between 4-6 months. Hopefully, the external imposition of a rhythm will entrain the brain to produce a normal rhythm of its own after this time.

In comparison to serum levels, salivary melatonin concentrations in the night time are generally lower. However the position of the melatonin profile (acrophase) does not differ within a subject in the concomitant measurement of serum and salivary melatonin. Therefore, the measurement of salivary melatonin levels seems valid for studies on melatonin rhythms (1)

(1) Maurizi C P : The therapeutical potential for tryptophan and melatonin: Possible roles in depression, sleep, Alzheimers disease and abnormal aging Medical Hyp1990)
Test Requirements:

The Salivary Sleep Profile & Melatonin Profile requires four saliva samples collected at specific times throughout the day, starting in the morning and finishing at midnight.
The Salivary Single Melatonin only requires a single sample collected at midnight or as required.