[Circadian oscillators and hormones]

Area of Science:

• Chronobiology
• Molecular endocrinology
• Gene regulation

Context:

• Circadian rhythms are fundamental biological processes influenced by internal clock genes.
• Hormonal regulation of these molecular clocks is complex and not fully understood.
• Clock proteins play a crucial role in mediating circadian rhythms and hormone secretion.

Purpose:

• To review the intricate relationship between hormonal systems and circadian clock proteins.
• To analyze the hormonal control mechanisms governing clock gene transcription and protein modification.
• To discuss the function of clock proteins as second messengers in hormonal signaling pathways.

Summary:

• The review examines how clock proteins, through direct action and regulation of clock-controlled genes, establish and maintain circadian rhythms, including hormone secretion.
• It delves into the hormonal control of circadian oscillators, focusing on clock gene transcription and posttranslational modifications of clock proteins.
• Clock proteins are presented as key mediators (second messengers) in hormonal actions, linking endocrine signals to the molecular clock.

Impact:

• Provides a comprehensive overview of hormonal influences on circadian clockworks.
• Enhances understanding of how hormones synchronize diverse biological rhythms (ultradian, circadian, circannual).
• Identifies clock proteins as critical nodes in integrating hormonal signals with cellular timekeeping mechanisms.