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Absence of an increase in the duration of the circadian melatonin secretory episode in totally blind human subjectsThe daily rhythm of melatonin influences multiple physiological measures, including sleep tendency, circadian rhythms, and reproductive function in seasonally breeding mammals. The biological signal for photoperiodic changes in seasonally breeding mammals is a change in the duration of melatonin secretion, which in a natural environment reflects the different durations of daylight across the year, with longer nights leading to a longer duration of melatonin secretion. These seasonal changes in the duration of melatonin secretion do not simply reflect the known acute suppression of melatonin secretion by ocular light exposure, but also represent long-term changes in the endogenous nocturnal melatonin episode that persist in constant conditions. As the eyes of totally blind individuals do not transmit ocular light information, we hypothesized that the duration of the melatonin secretory episode in blind subjects would be longer than those in sighted individuals, who are exposed to light for all their waking hours in an urban environment. We assessed the melatonin secretory profile during constant posture, dim light conditions in 17 blind and 157 sighted adults, all of whom were healthy and using no prescription or nonprescription medications. The duration of melatonin secretion was not significantly different between blind and sighted individuals. Healthy blind individuals after years without ocular light exposure do not have a longer duration of melatonin secretion than healthy sighted individuals.
Document ID
20040112375
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Klerman, E. B. (Brigham and Women's Hospital and Harvard Medical School Boston, Massachusetts 02115, United States)
Zeitzer, J. M.
Duffy, J. F.
Khalsa, S. B.
Czeisler, C. A.
Date Acquired
August 21, 2013
Publication Date
July 1, 2001
Publication Information
Publication: The Journal of clinical endocrinology and metabolism
Volume: 86
Issue: 7
ISSN: 0021-972X
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: K01-AG-00661
CONTRACT_GRANT: 1-R01-MH-45130
CONTRACT_GRANT: F33-HL-09588
CONTRACT_GRANT: 1-R01-AG-06072
CONTRACT_GRANT: MH-18825-12
CONTRACT_GRANT: M01-RR-02635
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
NASA Discipline Regulatory Physiology