The Circadian Timing System and Endocrine Physiolo

Authors: Michael T Sellix

Publish Date: 2016

Volume: , Issue: , Pages: 57-102

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Abstract

From the pineal gland to the endocrine pancreas the circadian timing system drives rhythms of hormone synthesis and secretion Observation of rhythmic hormone secretion stimulated discovery in the field of chronobiology for well over a century and continues to present new and exciting challenges Much of what we know about the biological basis of timing in physiology is fruit born of an effort to characterize the basis of hormonal oscillations The advent of applied molecular genetics in circadian biology ushered in a wave of discovery leading to characterization of the molecular basis of circadian rhythms in mammals With this discovery came the revelation that nearly every cell and tissue in mammals harbors a circadian clock a selfregulating transcription based oscillator of genetic regulatory factors This benchmark stimulated an explosion of interest in the role for the molecular clock in the timing and amplitude of cellular and organismal physiology As a field interest rapidly turned to the elegant and persistent rhythms of hormone secretion With this renewed focus the last 10–15 years have been a time of highpaced discovery We now know a great deal about molecular clock function in each of the major endocrine organs including the pituitary gland adrenal gland pineal gland gonads adipose tissue and endocrine pancreas The impact of altered clock function in these tissues on physiology suggests strong functional links between the timing and endocrine systems Understanding the depth and breadth of this integration will allow us to appreciate the complex mechanisms of basic endocrine physiology and possibly provide new and exciting avenues for the treatment of devastating and complex endocrine disorders

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