Secreted by the pineal gland of the brain in the absence of light, melatonin is often referred to as the "sleep hormone". However, the discovery of Professor Jean-Bernard Fourtillan, revealed in 2015 at the Academy of Pharmacy in Paris, calls everything into question.
It dates from 1994, Professor Fourtillan succeeding in deciphering the hormonal cascade regulating the sleep-wake system and involving this “new” hormone, called valentonine in reference to his little daughter Valentine.
We are talking here about valentonine, a real sleep hormone, melatonin, a neuroprotective hormone, and 6-methoxy-harmalan, the wakefulness hormone.
They would still be produced by the pineal gland between 10 p.m. and 6 a.m. Within a few minutes depending on the individual, but within this specific time slot, regardless of the time of year.
The three hormones would be secreted at the same time, however in different proportions, allowing the one present in greater quantity to impose its effect. Thus, between 10 p.m. and 6 a.m., valentonine being predominant, it would keep us asleep. However, arrived at 6 am, valentonine and melatonin would be eliminated very quickly. 6-methoxy-harmalan would be eliminated much more slowly. Thus, its significant predominance would keep us awake throughout the day.
As we have seen, it is not this that puts the body to rest, although it does greatly contribute to it.
Due to its chemical composition, it traps free radicals present in the body. It is then reduced to 2-oxo-melatonin, which will be eliminated through the blood. As such, melatonin plays the essential role of antioxidant and neuroprotector. Indeed, it becomes necessary to get into a good sleep to deoxidize the neurons, which have been very stressed all day.
It is also used as a marker in the analysis of other hormones because a deficit in melatonin necessarily implies a deficit of other hormones. Given their cascade biosynthesis, the 3 pineal hormones are always secreted in the same proportions. We then face a sleep AND wakefulness disorder. One does not go without the other.
"Happiness hormone", it comes from the transformation of tryptophan, which is found in food. A real starting point for the synthesis of other pineal hormones, it successively gives rise to melatonin, 6-methoxy-harmalan, then valentonine thanks to a process of complex “biochemical cascades” (enzymatic acetylations).
Although the synthesis of serotonin is stimulated by daylight, the true hormone of wakefulness and vigilance remains 6-methoxy-harmalan, whose pharmacological properties are exactly the opposite of those of valentonin.
For a long time, it was believed that the only hormone secreted by the pineal gland was melatonin. It was then given the name of the sleep hormone, believing that it was it that put the body to rest. However, the discovery of valentonine by Professor Jean-Bernard Fourtillan shows us something else.
All this shakes up a little what we knew or thought we knew. The work of Professor Fourtillan, still controversial among the medical community, still deserves special attention, since it is only by looking that we find, and the only thing that never changes is that everything changes all the time!
Fourtillan, Jean-Bernard. (2016). La glande pinéale et le système Veille-Sommeil. Les Éditions Fonds Sœur Josefa Menendez, Poitiers, 216 p.