Melatonin is a biogenic amine that is found in animals, plants and microbes. Aaron B. Lerner of Yale University is credited for naming the hormone and for defining its chemical structure in 1958. In mammals, melatonin is produced by the pineal gland. The pineal gland is small endocrine gland, about the size of a rice grain and shaped like a pine cone (hence the name), that is located in the center of the brain (rostro-dorsal to the superior colliculus) but outside the blood-brain barrier. The secretion of melatonin increases in darkness and decreases during exposure to light, thereby regulating the circadian rhythms of several biological functions, including the sleep-wake cycle. In particular, melatonin regulates the sleep-wake cycle by chemically causing drowsiness and lowering the body temperature. Melatonin is also implicated in the regulation of mood, learning and memory, immune activity, dreaming, fertility and reproduction. Melatonin is also an effective antioxidant. Most of the actions of melatonin are mediated through the binding and activation of melatonin receptors. Individuals with autism spectrum disorders (ASD) may have lower than normal levels of melatonin. A 2008 study found that unaffected parents of individuals with ASD also have lower melatonin levels, and that the deficits were associated with low activity of the ASMT gene, which encodes the last enzyme of melatonin synthesis. Reduced melatonin production has also been proposed as a likely factor in the significantly higher cancer rates in night workers.
There is no data for the T-value. The environmental information comes from Fass.se. Below is Hazard and Risk from Fass environmental information for Circadin (melatonin) (downloaded 2018-07-03) Hazard Persistence: Data not available. Bioaccumulation: Log Pow = 1.65 Chronic toxicity: Data not available. Risk "Risk of environmental impact of melatonin cannot be excluded, since there is not sufficient ecotoxicity data available." Below is environmental information from the assessment report for Circadin (melatonin) EMEA/H/C/695 "PECsurface water 0.00002 μg/L. The correct value is above the trigger value of 0.01 μg/l and therefore phase II studies are in principle needed. The applicant was requested to discuss the need for such studies. The re-calculated the PEC surface water on the basis of the new posology (2 mg/day) and the administration schedule proposed (3 weeks followed by 2 months interval, resulting in 15 weeks of exposure), resulted in a value below the trigger limit. Therefore further phase II studies were not requested by the CHMP considering that Circadin, at the recommended posology, did not present any potential risk to the environment."
Fass.se för vårdpersonal
European Medicines Agency. European public assessment reports (EPAR).