Melatonin - key hormone of circadian biorhythms
For more than 15 years BUHLMANN provides the gold standard in immunological determination of Melatonin. The hormone produced by the pineal gland is the most important in vitro marker to assess the individual circadian and seasonal biorhythm. In close contact with the scientific community of chronobiologists, BÜHLMANN has set up the Sleep Check application, providing a routine tool to determine individual shifts in sleep-wake cycles.
CIRCADIAN RHYTHM DISORDERS
Delayed-sleep-phase syndrome is a disorder in which nightly sleep is delayed until long after the desired sleep time (not before 2:00 a.m.). This results in sleep onset association disorder, excessive daytime sleepiness and trouble waking up at the desired time (not before 10:00 a.m.).
Advanced-sleep-phase syndrome is a disorder in which nightly sleep and irresistible sleepiness come before the desired time (between 6:00 and 9:00 p.m.). The patient wakes up earlier than desired (2:00 to 5:00 a.m.) in the morning.
Other circadian rhythm disorders are Jet lag syndrome, shift-work sleep disorder, irregular sleep-wake rhythm syndrome and 24-hour sleep-wake syndrome which are classified as sleep and circadian rhythm disorders, too.
There are diseases associated with sleep and circadian rhythm disorders like mood disorders, seasonal affective disorders (SAD), chronic fatigue syndrome (CFS), chronic sleep onset insomnia in children with the so called attention deficit hyperkinesias disorder (ADHD) that manifest similar sleep disturbances.
MELATONIN AND CIRCADIAN RHYTHM DISORDERS
Melatonin plays an important role in the synchronisation and characterisation of sleep-wake cycles. Endogenous melatonin is a hormone produced in the pineal gland during the dark phase of the day-night cycle. Its secretion is controlled by an endogenous oscillator that is entrained by light. Daytime melatonin levels are low or even undetectable and rise in the evening during decreasing light intensity.
The onset point of melatonin secretion under dim light conditions is called DLMO (Dim Light Melatonin Onset). In contrast to other circadian markers like cortisol, melatonin is the preferred circadian marker because of its robustness even in the presence of various exogenous factors like mental pressure or others.
DIM LIGHT MELATONIN ONSET
DLMO is considered to be the most useful parameter of the 24 hour melatonin curve and is the recommended parameter to diagnose sleep and circadian rhythm disorders. The easiest way to assess the DLMO, melatonin can be determined in saliva samples collected by the patient himself.
In most cases, it‘s not necessary to determine a 24 hours profile which is more difficult to collect. In fact, a partial melatonin profile, composed of 5 saliva sample collected hourly around bed time is sufficient to asses DLMO (see Sleep Check). In adults the normal DLMO time points are around 07:30 p.m. to 10:00 p.m. An abnormal timing of DLMO indicate a sleep and circadian rhythm disorders and provides a clue for the optimal timing of treatment with exogenous Melatonin or bright light.
BÜHLMANN offers most sensitive Immunoassays to measure any kind of biological sample by either RIA or ELISA technique. Because Melatonin is a conservative molecule, its immunological quantification is not restricted to humans alone. Even plants synthesises this hormone.
|Sample Volume||800 µl||800 µl||200 µl||10 µl|
|Time to Result||24 h||24 h||24h||4.5 h|
|Standard Range||0.5 - 50
|0.5 - 50 pg/ml||0.6 - 25 pg/ml||0.8 - 40 ng/ml|
We are participating in the multicenter EUCLOCK research project which is conducted under the Sixth Framework Programme funded by the European Commission.
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