Part of “CHAPTER 10 – PINEAL GLAND“

The human pineal gland is a highly active organ that secretes at least one indole hormone, melatonin, and possibly several other active substances, either indoleamines or peptides. Assays are available to measure melatonin in bodily fluids34 and its metabolites in the urine. The cyclic production of melatonin is highly characteristic, with highest levels occurring during the dark/sleep phase. The consequences of altered melatonin rhythms are incompletely understood but likely relate to several clinical entities. In addition, some persons probably have an excess (hypermelatoninism)17 or deficiency (hypomelatoninism)35 in melatonin production and secretion.