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Unformatted text preview: Article 4 Rhythmic gene expression in pituitary depends in herterologous sensitization by the neurohormone melatonin Abstract-mammalian daily cycles are driven by a circadian clock-clock is based on the cell-autonomous rhythmic expression of clock genes-cycling expression of Period 1 (a clock gene) in the pituatory gland depends on heterologous sensitization of the adenosine A 2b receptor-this happens by the nighttime activation of the melatonin mt1 receptors-eliminating melatonin suppresses the expression of Period 1 and increases the release of prolactin from the pituitary Introduction-if gene expression in not temporally correct, cellular malfunction and disease can result-hypothalamic suprachiasmatic nucleus (SCN):-partitions metabolic functions in 24 hour cycle-24 hour rhythm is regulated by transcription/translation feedback loops -PERIOD in humans in a transcription/translation feedback loop-PERIPHERAL RHYTHMS:-circadian rhythms are not limited to the cells of the SCN, they can be found in many tissues, but with a delayed timing with respect to the SCN-peripheral rhythms dampen in vitro after a few cycles b/c they depend on neuronal and/or neuroendocrine signals from the SCN-when the SCN and peripheral clock-controlled genes are not in synch, jet-lag and shift-work pathologies result-both neural and endocrine pathways can maintain circadian gene expression in the periphery:- Period (Per) gene rhythms can be regulated by glucocorticoids and cycles of restricted feeding in rodents-in rodent pineal gland:...
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This note was uploaded on 02/05/2012 for the course BIOLOGY 3u3 taught by Professor Dr.rollo during the Spring '11 term at McMaster University.
- Spring '11