Bimodal patterns of human melatonin secretion consistent with a two-oscillator model of regulation

• Published in: Neuroscience letters Vol. 194; no. 1; pp. 105 - 108
• Main Authors: Wehr, Thomas A., Schwartz, Paul J., Turner, Erick H., Feldman-Naim, Susana, Drake, Christopher L., Rosenthal, Norman E.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 14.07.1995; Elsevier
• Subjects: Adult; Biological and medical sciences; Circadian Rhythm; Female; Fundamental and applied biological sciences. Psychology; Hormones and neuropeptides. Regulation; Humans; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Light; Melatonin; Melatonin - blood; Melatonin - metabolism; Middle Aged; Models, Biological; Photoperiod; Season; Seasonal Affective Disorder; Seasons; Time Factors; Vertebrates: endocrinology; Seasonal affective disorder; Melatonin; Photoperiod; Circadian rhythm; Season; Light; Human; Secretion; Biological rhythm; Melatonine; Pineal hormone
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/0304-3940(95)11740-N

In many animals, changes in duration of nocturnal melatonin secretion chemically mediate effects of seasonal changes in nightlength on behavior and physiology. According to one model, the changes in duration of secretion result from adjustments in the timing of two circadian oscillators, one entrained to dusk, controlling onset, and another entrained to dawn, controlling offset. Consistent with this model, in six women, we found separate and reproducible evening and morning peaks of melatonin secretion that might represent the separate expressions of rhythms of two oscillators.