These authors contributed equally.
Transcription factor dynamics in pineal gland and liver of the Syrian hamster (Mesocricetus auratus) adapts to prevailing photoperiod
Article first published online: 29 MAR 2007
Journal of Pineal Research
Volume 43, Issue 1, pages 16–24, August 2007
How to Cite
Maronde, E., Pfeffer, M., Glass, Y. and Stehle, J. H. (2007), Transcription factor dynamics in pineal gland and liver of the Syrian hamster (Mesocricetus auratus) adapts to prevailing photoperiod. Journal of Pineal Research, 43: 16–24. doi: 10.1111/j.1600-079X.2007.00438.x
- Issue published online: 6 APR 2007
- Article first published online: 29 MAR 2007
- Received December 18, 2006; accepted February 20, 2007.
- clock genes;
- inducible cAMP early repressor;
Abstract: The anticipation of day length and duration of darkness is necessary and advantageous for animals to survive and requires a photoperiodic memory. In the Syrian hamster this adaptation to photoperiod is mirrored by seasonal changes in the animal's reproductive state and its liver metabolism. Both events are linked to season-dependent alterations of the nocturnally elevated synthesis of the pineal hormone melatonin. To decipher molecules that are involved in this temporal gating, hamsters were exposed to long photoperiod (16 hr light:8 hr darkness; LP), or short photoperiod (8 hr light:16 hr darkness; SP). Dynamics in gene expression was investigated in the pineal gland [inducible cAMP early repressor (ICER)], and in the liver (ICER; C/EBPδ; clock genes) using immunochemistry and reverse transcriptase PCR. While in the pineal, ICER rhythms tightly follow the prior duration of light and dark with decreasing levels at the beginning of the dark period in both LP and SP, ICER is not rhythmic in liver. In the liver, clock genes and their protein products reflect differences in photoperiodic history, with enhanced rhythm amplitudes of PER, CRY, CLOCK, and BMAL1 under SP conditions. Thus, in the Syrian hamster transcription factor expression patterns lock onto the prevailing photoperiod in two peripheral oscillators, the pineal gland and the liver, to function as mediators of suprachiasmatic nucleus-derived information on environmental light and dark. This tissue-specific gating in gene transcription represents a strategy to ameliorate consequences of altering environmental lighting conditions on endocrine and metabolic parameters that endow a strong circadian bias.