Description_x000D_ General description_x000D_ Melatonin (N-acetyl-5-methoxytryptamine) is synthesized from an essential amino acid tryptophan. It is a pineal gland neurohormone. Direct, non-receptor-mediated free radical scavenging activity induced by melatonin, makes it unique from other classic hormones. Melatonin is expressed in variety of organisms such as bacteria, algae, fungi, plants, insects, and vertebrates including humans._x000D_ Application_x000D_ Melatonin has been administered to experimental animals for following studies:_x000D_ • To determine if long-term melatonin administration is able to induce reproductive changes and how melatonin exerts its protective action related to lipid oxidation and antioxidant activities in the rat ovary during ovulation._x000D_ • To determine the effect of melatonin on endoplasmic reticulum stress and sirtuin 1 expression in neuronal cells of newborn rats after hypoxia–ischemia._x000D_ • To study the effect of melatonin on chronic stress-induced gut dysfunction in stressed mice._x000D_ Packaging_x000D_ 1, 5, 10 g in glass bottle_x000D_ 250 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ Hormone; mediates photoperiodicity in mammals; inhibits cerebellar nitric oxide synthetase; peroxynitrite scavenger. Melatonin has complex effects on apoptotic pathways, inhibiting apoptosis in immune cells and neurons but enhancing apoptotic cell death of cancer cells. Inhibits proliferation/metastasis of breast cancer cells by inhibiting estrogen receptor action._x000D_ Melatonin is characterized with variety of properties such as antioxidant, autocoid, paracoid and hormonal properties, as well as anti- inflammatory and anti-apoptotic properties. Melatonin is implicated in the regulation of seasonal reproduction, energy metabolism and thermoregulation in mammals. Melatonin plays a vital role in the lessening of neonatal hypoxia–ischemia (HI) induced endoplasmic reticulum (ER) stress and conserves sirtuin 1( SIRT-1) expression._x000D_ Features and Benefits_x000D_ This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more._x000D_ Caution_x000D_ Solutions are light sensitive and subject to oxidation._x000D_ Other Notes_x000D_ Tandem Mass Spectrometry data independently generated by Scripps Center for Metabolomics is available to view or download in PDF. M5250.pdf Tested metabolites are featured on Scripps Center for Metabolomics METLIN Metabolite Database. To learn more, visit sigma.com/metlin._x000D_ Legal Information_x000D_ LOPAC is a registered trademark of Sigma-Aldrich Co. LLC