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Circadian rhythms of plasma melatonin in the ruin lizard Podarcis sicula: Effects of pinealectomy
Author(s) -
Foa Augusto,
Janik Daniel,
Minutini Lucia
Publication year - 1992
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.1992.tb00036.x
Subject(s) - pinealectomy , melatonin , circadian rhythm , rhythm , medicine , biology , endocrinology , period (music) , darkness , pineal gland , lizard , zoology , botany , physics , acoustics
Plasma melatonin was measured in lizards ( Podarcis sicula ) at six different times of day under conditions of constant temperature and darkness. Intact animals showed a circadian rhythm of melatonin with a peak in the subjective night of 207 pg/ml (median) and a trough during the subjective day that was below the minimum detection level of the assay (50 pg/ml). Pinealectomy abolished the circadian rhythm of plasma melatonin; median levels were near or below the minimum detection level at all times sampled. The data suggest that the pineal is the only source of rhythmic blood‐borne melatonin in Podarcis sicula , and are consistent with the hypothesis that changes in the free‐running period of the locomotor rhythm induced by pinealectomy in this species are due to withdrawal of rhythmic melatonin from the blood.