Clocks within the Master Gland: Hypophyseal Rhythms and Their Physiological Significance.
Various aspects of mammalian endocrine physiology show a time-of-day variation with a period of 24 h, which represents an adaptation to the daily environmental fluctuations resulting from the rotation of the earth. These 24-h rhythms in hormone abundance and consequently hormone function may rely on rhythmic signals produced by the master circadian clock, which resides in the suprachiasmatic nucleus and is thought to chiefly dictate the pattern of rest and activity in mammals in conjunction with the light/dark (LD) cycle. However, it is likely that clocks intrinsic to elements of the endocrine axes also contribute to the 24-h rhythms in hormone function. Here we review the evidence for rhythm generation in the endocrine master gland, the pituitary, and its physiological significance in the context of endocrine axes regulation and function.
Department of Psychiatry, McGill University, Montreal, Quebec, Canada Douglas Mental Health University Institute, Montreal, Quebec, Canada Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada.
Xue-Wei
XW
Lin
Department of Psychiatry, McGill University, Montreal, Quebec, Canada Douglas Mental Health University Institute, Montreal, Quebec, Canada Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada.
Ian David
ID
Blum
Department of Psychiatry, McGill University, Montreal, Quebec, Canada Douglas Mental Health University Institute, Montreal, Quebec, Canada florian.storch@mcgill.ca.
Kai-Florian
KF
Storch
D000818:Animals; D057906:Circadian Clocks / Q000235:genetics* / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D015870:Gene Expression; D006728:Hormones / Q000502:physiology; D008322:Mammals; D010507:Periodicity; D017440:Photoperiod; D010902:Pituitary Gland / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000502:physiology
D006728:Hormones
endocrine physiology; hormone release; intrinsic rhythmicity; peripheral clocks; pituitary gland