The Metabolism of Melatonin (IV-Acetyl-5-methoxytryptamine) and 5=Methoxytryptamine*“f

The potent frog skin-lightening agent “melatonin” was isolated from pineal tissue and characterized as N-acetyl-5-methoxytryptamine by Lerner, Case, and Takahashi (1). Recently, Axelrod and Weissbach (2), studying the biogenesis of this hormone, have shown it to be the product of a specific methylating enzyme system in the pineal gland which acts on the substrate N-acetylserotonin, a substance previously found to be a metabolite of serotonin by McIsaac and Page (3). Another compound isolated from pineal tissue proved to be 5-methoxyindoleacetic acid (l), and there have been some differences of opinion regarding the biogenesis of this compound. To study the metabolic fate of melatonin and the biogenesis of 5-methoxyindole acetic acid, N-acetyl-5-methoxytryptamine-fiCl4 and 5-methoxytryptamine-P_C’4 were synthesized.