title: High melatonin solubility in aqueous medium.
abstract: The pineal hormone melatonin (5-methoxy-N-acetyl-tryptamine) has been reported to participate in important physiological processes. Although some of its biological actions seem to depend on a protein receptor at the membrane surface, melatonin is known to interact with a large variety of tissues and cells, suggesting that the molecule may not necessarily interact through a specific membrane receptor at a specific cell. Most discussions of melatonin activity have assumed that the molecule is highly hydrophobic. Contrary to belief, the present work shows that melatonin is soluble in a purely aqueous medium up to 5 x 10(-3) M and describes a new method of melatonin preparation which shows the high hydrophilicity of the molecule. The results presented will affect the current biological hypothesis on the need of a melatonin carrier in the blood stream or the mechanisms which allow the hormone to cross the cell membrane and interact at the level of the nucleus.
authors: Instituto de Fisica, Universidad de São Paulo, Brazil.
authors: C S
authors: CS
authors: Shida
authors: A M
authors: AM
authors: Castrucci
authors: M T
authors: MT
authors: Lamy-Freund
mesh_terms: D000818:Animals; D001681:Biological Assay; D002025:Bufonidae; D002352:Carrier Proteins; D008550:Melatonin / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry*
chemical_list: D002352:Carrier Proteins; D014867:Water; D008550:Melatonin