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Investigation of Circadian Rhythms for Pineal 5‐Hydroxytryptophol and Other Indoles in the Rat
Author(s) -
Foley Paul B.,
Cairncross Keith D.
Publication year - 1987
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1987.tb00846.x
Subject(s) - melatonin , circadian rhythm , pineal gland , medicine , endocrinology , serotonin , period (music) , biology , hormone , 5 ht receptor , receptor , physics , acoustics
5‐hydroxytryptophol (5HTL) occurs in the pineal gland of the rat at levels comparable to those of melatonin, yet few studies have been conducted to investigate 5HTL as a potential alternative pineal hormone. In this study the pineals of 90‐day‐old male Sprague Dawley rats have been assayed by high performance liquid chromatography coupled with electrochemical detection. Significant ( P < .0001) circadian variation was measured in 5HTL levels, and a fivefold plateau elevation occured during the middle of the light period. By comparison with the timing of the variations in N‐acetyl serotonin and melatonin levels, it is suggested that 5HTL may not be regulated by simple competition with N‐acetyl transferase for the common substrate 5HT but may, in fact, be regulated independently. Literature supporting such a suggestion, and a model incorporating it, are presented for discussion.