Abstract
Pineal function was assessed in human subjects by measuring the excretion of melatonin. The hormone was extracted from the urine by adsorption on a nonionic polymeric resin and then elution with organic solvents; its concentration was determined with a bioassay based ontthe dermal melanophore response of larval anurans to melatonin in their bathing medium. Melatonin excretion among healthy, adult volunteers was 5- to 7-fold greater during the hours of sleep, darkness, and recumbancy (23:00–07:00 h) than during the active, waking hours (07:00–15:00 h or 15:00–23:00 h). When 2 subjects slept only during the daylight at odd, 8-hour intervals, their melatonin excretion was also greatest during their time of sleep. Three bedfast fracture patients (for whom sleep data were not available) failed to display melatonin rhythms. A new radioimmunoassay for melatonin was investigated in preliminary studies with experimental animals and was found to be expedient and sensitive; it was not as specific as the bioassay, however. Both analytical methods were used in studies on intact and pinealectomized rats, and the findings suggest that rhythmic melatonin excretion persists (although at a reduced amplitude) in the absence of the pineal. Fasting in the pinealectomized animal abolished the day/night variation in urinary melatonin, but did not have this effect in intact rats.
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Some of these studies have been previously described by H.J.Lynch and R.J.Wurtman in a paper presented at the symposium "Advances in Fertility Regulation Through Basic Research", which was held at Rockefeller University, New York, 15 and 16 July 1974, and was sponsored by the Center for Population Research of the National Institute of Child Health and Human Development.
Presented during the Seventh International Biometeorological Congress, 17–23 August 1975, College Park, Maryland, USA;
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Lynch, H.J., Ozaki, Y., Shakal, D. et al. Melatonin excretion of man and rats: Effect of time of day, sleep, pinealectomy and food consumption. Int J Biometeorol 19, 267–279 (1975). https://doi.org/10.1007/BF01451037
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DOI: https://doi.org/10.1007/BF01451037