Melatonin
Original Editor - Lucinda hampton
Top Contributors - Lucinda hampton and Vidya Acharya
Introduction[edit | edit source]
Melatonin, mostly released by the pineal gland, is a circadian rhythm-regulated and multifunctional hormone. Great advances in melatonin research have been made, including its role in rhythms of the sleep-wake cycle, retardation of ageing processes, as well as antioxidant or anti-inflammatory functions.
Endogenous melatonin is a hormone produced naturally, synthesized, and secreted primarily in the pineal gland. Melatonin is released from the pineal gland into the third ventricle and from there into circulation.
Roles of melatonin include:
- Melatonin is involved in regulating the body's sleep-wake cycles. Melatonin is sometimes called the “Dracula of hormones” because it only comes out in the dark.[1]
- Melatonin is very effective in reducing oxidative stress under a large number of situations. It achieves this action via a variety of means: direct detoxification of reactive oxygen and reactive nitrogen species and indirectly by stimulating antioxidant enzymes while suppressing the activity of pro-oxidant enzymes[2].
- Melatonin can scavenge free radicals such as reactive oxygen species (ROS), a key factor in reproductive functions. Melatonin plays an important role in oocyte maturation, fertilization and embryonic development as well.[3][4]
Synthesis of Endogenous Melatonin[edit | edit source]
The hormone melatonin is produced naturally, synthesized, and secreted mainly in the pineal gland. Melatonin production begins with tryptophan, which in a multistep process is converted to serotonin in other parts of the brain. Some serotonin made makes its way to the pineal gland and is converted to melatonin in a regularly, light-dependent process.
The conversion of serotonin to melatonin is controlled by the hypothalamus's suprachiasmatic nucleus (SCN), whose job is to control the body's circadian rhythms. Information about current light conditions travels from the retina along the retinohypothalamic tract to the SCN. From here signals are sent through the sympathetic nervous system to the superior cervical ganglia, which innervates the pineal gland[5].
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References[edit | edit source]
- ↑ Byjus Melatonin hormone Available:https://byjus.com/biology/melatonin-hormone/ (accessed 9.8.2022)
- ↑ Reiter RJ, Mayo JC, Tan DX, Sainz RM, Alatorre‐Jimenez M, Qin L. Melatonin as an antioxidant: under promises but over delivers. Journal of pineal research. 2016 Oct;61(3):253-78. Available: https://pubmed.ncbi.nlm.nih.gov/27500468/(accessed 9.8.2022)
- ↑ Yong W, Ma H, Na M, Gao T, Zhang Y, Hao L, Yu H, Yang H, Deng X. Roles of melatonin in the field of reproductive medicine. Biomedicine & Pharmacotherapy. 2021 Dec 1;144:112001. Available: https://pubmed.ncbi.nlm.nih.gov/34624677/ (accessed 9.8.2022)
- ↑ Wójtowicz M, Jakiel G. Melatonin and its role in human reproduction. Ginekologia polska. 2002 Dec 1;73(12):1231-7. Available:https://pubmed.ncbi.nlm.nih.gov/12722474/ (accessed 9.8.2022)
- ↑ Savage RA, Zafar N, Yohannan S. Melatonin.[Updated 2021 Aug 15]. StatPearls. 2021. Available:https://www.ncbi.nlm.nih.gov/books/NBK534823/ (accessed 9.8.2022)
