Please use this identifier to cite or link to this item: https://hdl.handle.net/2440/55094
Citations
Scopus Web of ScienceĀ® Altmetric
?
?
Type: Journal article
Title: Melatonin rhythms in the Australian freshwater crocodile (Crocodylus johnstoni): a reptile lacking a pineal complex?
Author: Firth, B.
Christian, K.
Belan, I.
Kennaway, D.
Citation: Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology, 2010; 180(1):67-72
Publisher: Springer
Issue Date: 2010
ISSN: 0174-1578
1432-136X
Statement of
Responsibility: 
Bruce T. Firth, Keith A. Christian, Ingrid Belan and David J. Kennaway
Abstract: The vertebrate pineal gland is the primary source of melatonin, the rhythmic secretion of which is influenced by environmental light and temperature, thereby providing animals with information about seasonally changing photoperiod and thermoperiod. Although pineal glands are present in the majority of vertebrate species, a discrete organ is reported to be absent in the Crocodilia. However, if the melatonin rhythm is crucial to the survival of the organism, it would be expected that the rhythm would be present in crocodiles. In the present study, we measured blood plasma melatonin over a 30-h period in aestivating Australian freshwater crocodiles (Crocodylus johnstoni) in their natural habitat at the end of the dry season (November) and found no discernible melatonin rhythm. However, another group of captive-reared C. johnstoni, maintained under natural light and temperature cycles and sampled in the early dry season (June) showed a clear melatonin rhythm. These results suggest that there is either an extrapineal source of melatonin in this crocodile species or that there is melatonin producing tissue elsewhere which heretofore has not been discovered. Further studies are needed to determine why the melatonin rhythm is intermittently expressed and whether this may be related to seasonal changes in the expression of the rhythm linked to tropical environments.
Keywords: Animals
Animals, Wild
Alligators and Crocodiles
Melatonin
Temperature
Seasons
Fresh Water
Adaptation, Biological
Circadian Rhythm
Photoperiod
Northern Territory
DOI: 10.1007/s00360-009-0387-8
Published version: http://dx.doi.org/10.1007/s00360-009-0387-8
Appears in Collections:Anatomical Sciences publications
Aurora harvest 5

Files in This Item:
There are no files associated with this item.


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.