Melatonin, Serotonin, 5-Hydroxyindole-3-Acetic Acid and N-Acetyltransferase in the Pineal of the European Hamster (Cricetus cricetus) Kept Under Natural Environmental Conditions: Lack of a Day/Night Rhythm in Melatonin Formation in Spring and Early Summer
Article first published online: 30 JAN 2007
Journal of Pineal Research
Volume 6, Issue 3, pages 233–242, July 1989
How to Cite
Pévet, P., Vivien-Roels, B., Masson-Pévet, M., Steinlechner, S., Skene, D. and Canguilhem, B. (1989), Melatonin, Serotonin, 5-Hydroxyindole-3-Acetic Acid and N-Acetyltransferase in the Pineal of the European Hamster (Cricetus cricetus) Kept Under Natural Environmental Conditions: Lack of a Day/Night Rhythm in Melatonin Formation in Spring and Early Summer. Journal of Pineal Research, 6: 233–242. doi: 10.1111/j.1600-079X.1989.tb00419.x
- Issue published online: 30 JAN 2007
- Article first published online: 30 JAN 2007
- Received June 13, 1988; accepted August 5, 1988.
- circadian rhythm;
- seasonal sexual cycle;
In female European hamsters killed in spring and early summer, pineal melatonin content exhibited no day/night rhythm. Absolute levels measured were relatively low, being on the order of daytime levels detected in other hamster species. An absence of day/night changes in the activity of N-acetyltransferase was also observed. However, a marked rhythm in pineal serotonin (5-HT) was found, an abrupt large increase being observed at the beginning of the light period. The day /night rhythm of pineal 5-HIAA content is similar to that of 5-HT. This absence of rhythm in pineal melatonin formation might mean that in the European hamster it is not melatonin but another substance that is of importance in photoperiodism. An absence of melatonin rhythm, however, could also be simply a peculiar pattern of melatonin production observed at a given period of the year. In this case, melatonin would be able to transduce photoperiodic information in the European hamster, as in other photope riodic species.