The circadian clock is an important internal time regulatory system for a range of physiological and behavioral rhythms within living organisms. Testosterone, as one of the most critical sex hormones, is essential for the development of the reproductive system, maintenance of reproductive function, and the overall health of males. The secretion of testosterone in mammals is characterized by distinct circadian rhythms and is closely associated with the regulation of circadian clock genes. Here we review the central and peripheral regulatory mechanisms underlying the influence of circadian clock genes upon testosterone synthesis. We also examined the specific effects of these genes on the occurrence, development, and treatment of common male diseases, including late-onset hypogonadism, erectile dysfunction, male infertility, and prostate cancer.
Testosterone/metabolism* ; Humans ; Male ; Circadian Clocks/genetics* ; Circadian Rhythm Signaling Peptides and Proteins/metabolism* ; Circadian Rhythm/physiology* ; Hypogonadism/metabolism* ; Erectile Dysfunction/metabolism* ; Infertility, Male/metabolism* ; Prostatic Neoplasms/metabolism* ; Men's Health

The cyanobacterial circadian clock has three relatively independent parts: the input path, the core oscillator, and the output path. The core oscillator is composed of three clock proteins: KaiA, KaiB, and KaiC. The interactions among these three proteins generate a rhythmic signal and convey the input signals to the output signals to maintain the accuracy and stability of the oscillation of downstream signals. Based on the cyanobacterial circadian clock and the structure, function, and interaction of the clock proteins of the core oscillator, combining the recent results from our laboratory, this review summarized the recent progresses of the molecular mechanism of KaiA in regulating KaiC's enzymatic activity, mediating phase reset of the oscillator, and competing with CikA for the binding site of KaiB.
Bacterial Proteins ; genetics ; metabolism ; Circadian Clocks ; genetics ; Circadian Rhythm Signaling Peptides and Proteins ; metabolism ; Cyanobacteria ; genetics ; Enzyme Activation ; genetics

The release of hormones and the metabolism of human body are controlled by the circadian rhythm related to sleep-wake cycle. Growth hormone, prolactin, thyroid stimulating hormone, cortisol, glucose, and insulin-secretion rates fluctuate according to the sleep-wake cycle. In addition, sleep is related to the appetite regulation and carbohydrate and other energy metabolism. Hypocretin (orexin), an excitatory neuropeptide, regulates waking and diet intake, and the poor sleep increases diet intake. The short sleep duration increases one's body mass index and impairs the function of the endocrine and metabolism, causing increases in the risk of glucose intolerance and diabetes. The poor sleep quality and sleep disorders have similar impact on the metabolic function. In short, the sleep loss and the poor quality of sleep have a detrimental effect on the endocrine and energy metabolism. The improvement of sleep quality by the future research and appropriate clinical treatment would contribute to the decrease of the metabolic diseases such as diabetes.
Appetite Regulation ; Body Mass Index ; Circadian Rhythm ; Diet ; Energy Metabolism ; Glucose ; Glucose Intolerance ; Growth Hormone ; Human Body ; Hydrocortisone ; Intracellular Signaling Peptides and Proteins ; Metabolic Diseases ; Neuropeptides ; Prolactin ; Sleep Wake Disorders ; Thyrotropin ; Orexins