Expression and regulation of Icer mRNA in the Syrian hamster pineal gland

Generation of the Melatonin Endocrine Message in Mammals: A Review of the Complex Regulation of Melatonin Synthesis by Norepinephrine, Peptides, and Other Pineal Transmitters

“…The mechanisms controlling MEL synthesis in the Syrian hamster, therefore, appear somehow different to those described in the rat AA-NAT gene transcription, enzyme activation, and MEL synthesis during the night require the neosynthesis of a stimulatory protein (possibly transcription factor) but are repressed during the day by an inhibitory protein (possibly ICER), these processes leading to a strong gating of MEL synthesis in the late night (Diaz et al, 2003;Garidou et al, 2003a).…”

Daytime Gating in the Syrian Hamster Pineal Gland

“…6). By contrast to Icer mRNA (15), ICER protein was expressed at all time points of the 24‐h rhythm. CREB was constantly expressed over 24 h with no significant rhythm.…”

“…The nocturnal increase in c‐Fos protein (9) and Icer mRNA (15) in the Syrian hamster pineal gland is known to depend on the β1/cAMP pathway. The effect of a protein synthesis inhibitor was examined to find out whether this cAMP driven transcriptional activation depends solely upon pCREB or requires neosynthesised transcription factors, as reported for Aa‐nat transcription (8).…”

“…Pineal expression of c ‐fos and Icer 1 h after injection was examined by in situ hybridisation. In this experiment, two adrenergic agonists were used for c ‐fos because both α‐ and β‐adrenergic stimulation is required for its full induction (9); isoproterenol alone was used for Icer because a β‐adrenergic stimulation is sufficient for its full induction (15).…”

“…In previous studies, we reported a fast NE‐driven induction of c‐Fos protein (9) and Icer mRNA (15) at night‐time in the Syrian hamster pineal gland. Moreover, both c ‐fos and Icer gene expression are subjected to the inhibitory action of ICER in other models: Icer (4, 16) and c ‐fos (17, 18).…”