• Dr. Arun Mukherjee

Melatonin (N-acetyl-5-methoxytryptamine) was first isolated and identified as the hormone from pineal gland (Lerner et al., 1958). Its name is indicative of melatonin’s first identified function, its skin-lightening properties in fish and amphibians. However, alteration in skin coloration is not applicable to mammals. In mammals melanocytes are devoid of physiologically controlled mobile melanosomes. The hormone received considerable attention when it was found to regulate circadian rhythms (Armstrong et al., 1986). In photoperiodic organisms melatonin is involved in the measurement of day length (photoperiodic time measurement, PTM), an environmental variable used for seasonal timing of reproduction, metabolism and behaviour (Reiter, 1991). Melatonin is produced from the amino acid tryptophan depending on the length of dark period of the light-dark cycle. The occurrence of melatonin is not restricted to vertebrates, but is almost ubiquitously present in numerous taxa including, e.g., bacteria, unicellular eukaryotes and plants (Paredes et al., 2009) indicating that this molecule has gained many additional functions during the course of evolution (Tan et al., 2010). Melatonin displays an exceptional multiplicity in its actions. These can only be understood on the basis of an integrative, orchestrating role by which melatonin is distinguished from many other important signalling molecules. Besides acting as a chronobiotic neurohormone, melatonin also acts as a potent antioxidant, immune-booster, anti-apoptotic and anti-aging molecule. In the present review the pathway of melatonin biosynthesis and its photic regulation is being summarized.

Melatonin, Bissynthesis, AA-NAT, HIOMT,

"REGULATION OF MELATONIN BIOSYNTHESIS: A REVIEW", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 3, page no.741-744, March-2019, Available :http://www.jetir.org/papers/JETIR1903K14.pdf

"REGULATION OF MELATONIN BIOSYNTHESIS: A REVIEW", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 3, page no. pp741-744, March-2019, Available at : http://www.jetir.org/papers/JETIR1903K14.pdf