scholarly journals MECHANISMS IN ENDOCRINOLOGY: A sense of time of the glucocorticoid circadian clock: from the ontogeny to the diagnosis of Cushing’s syndrome

2018 ◽  
Vol 179 (1) ◽  
pp. R1-R18 ◽  
Author(s):  
Ayrton Custodio Moreira ◽  
Sonir Rauber Antonini ◽  
Margaret de Castro
Keyword(s):  
Circadian Rhythm ◽  
Circadian Clock ◽  
Clock Genes ◽  
Circadian Variation ◽  
Circadian System ◽  
Feedback Loops ◽  
Adrenal Axis ◽  
Sense Of Time ◽  
Pituitary Adrenal Axis ◽  
Hierarchical Manner

The circadian rhythm of glucocorticoids has long been recognised within the last 75 years. Since the beginning, researchers have sought to identify basic mechanisms underlying the origin and emergence of the corticosteroid circadian rhythmicity among mammals. Accordingly, Young, Hall and Rosbash, laureates of the 2017 Nobel Prize in Physiology or Medicine, as well as Takahashi’s group among others, have characterised the molecular cogwheels of the circadian system, describing interlocking transcription/translation feedback loops essential for normal circadian rhythms. Plasma glucocorticoid circadian variation depends on the expression of intrinsic clock genes within the anatomic components of the hypothalamic–pituitary–adrenal axis, which are organised in a hierarchical manner. This review presents a general overview of the glucocorticoid circadian clock mechanisms, highlighting the ontogeny of the pituitary–adrenal axis diurnal rhythmicity as well as the involvement of circadian rhythm abnormalities in the physiopathology and diagnosis of Cushing’s disease.

scholarly journals Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

2021 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Andy W. C. Man ◽  
Huige Li ◽  
Ning Xia
Keyword(s):  
Circadian Rhythm ◽  
Cardiovascular Diseases ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Therapeutic Target ◽  
Environmental Changes ◽  
Clock Genes ◽  
Vascular System ◽  
Peripheral Tissues ◽  
Inflammatory Processes

Every organism has an intrinsic biological rhythm that orchestrates biological processes in adjusting to daily environmental changes. Circadian rhythms are maintained by networks of molecular clocks throughout the core and peripheral tissues, including immune cells, blood vessels, and perivascular adipose tissues. Recent findings have suggested strong correlations between the circadian clock and cardiovascular diseases. Desynchronization between the circadian rhythm and body metabolism contributes to the development of cardiovascular diseases including arteriosclerosis and thrombosis. Circadian rhythms are involved in controlling inflammatory processes and metabolisms, which can influence the pathology of arteriosclerosis and thrombosis. Circadian clock genes are critical in maintaining the robust relationship between diurnal variation and the cardiovascular system. The circadian machinery in the vascular system may be a novel therapeutic target for the prevention and treatment of cardiovascular diseases. The research on circadian rhythms in cardiovascular diseases is still progressing. In this review, we briefly summarize recent studies on circadian rhythms and cardiovascular homeostasis, focusing on the circadian control of inflammatory processes and metabolisms. Based on the recent findings, we discuss the potential target molecules for future therapeutic strategies against cardiovascular diseases by targeting the circadian clock.

The Circadian Clock inArabidopsisRoots Is a Simplified Slave Version of the Clock in Shoots

Science ◽  
2008 ◽  
Vol 322 (5909) ◽  
pp. 1832-1835 ◽  
Author(s):  
Allan B. James ◽  
José A. Monreal ◽  
Gillian A. Nimmo ◽  
Ciarán L. Kelly ◽  
Pawel Herzyk ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Circadian Clock ◽  
Clock Genes ◽  
Plant Cells ◽  
Feedback Loops ◽  
Circadian Oscillator ◽  
Inhibit Gene Expression ◽  
Organ Specific ◽  
Plant Clock

The circadian oscillator in eukaryotes consists of several interlocking feedback loops through which the expression of clock genes is controlled. It is generally assumed that all plant cells contain essentially identical and cell-autonomous multiloop clocks. Here, we show that the circadian clock in the roots of matureArabidopsisplants differs markedly from that in the shoots and that the root clock is synchronized by a photosynthesis-related signal from the shoot. Two of the feedback loops of the plant circadian clock are disengaged in roots, because two key clock components, the transcription factors CCA1 and LHY, are able to inhibit gene expression in shoots but not in roots. Thus, the plant clock is organ-specific but not organ-autonomous.

OPIATE MODULATION OF THE PITUITARY-ADRENAL AXIS: EFFECTS OF STRESS AND CIRCADIAN RHYTHM

1982 ◽  
Vol 17 (3) ◽  
pp. 279-286 ◽  
Author(s):  
A. GROSSMAN ◽  
R. C. GAILLARD ◽  
P. McCARTNEY ◽  
LESLEY H. REES ◽  
G. M. BESSER
Keyword(s):  
Circadian Rhythm ◽  
Adrenal Axis ◽  
Effects Of Stress ◽  
Pituitary Adrenal Axis

scholarly journals “Gut Microbiota-Circadian Clock Axis” in Deciphering the Mechanism Linking Early-Life Nutritional Environment and Abnormal Glucose Metabolism

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Liyuan Zhou ◽  
Lin Kang ◽  
Xinhua Xiao ◽  
Lijing Jia ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Circadian Rhythm ◽  
Gut Microbiota ◽  
Circadian Clock ◽  
Early Life ◽  
Metabolic Diseases ◽  
Clock Genes ◽  
Early Stage ◽  
Adult Life ◽  
Metabolic Memory

The prevalence of diabetes mellitus (DM) has been increasing dramatically worldwide, but the pathogenesis is still unknown. A growing amount of evidence suggests that an abnormal developmental environment in early life increases the risk of developing metabolic diseases in adult life, which is referred to as the “metabolic memory” and the Developmental Origins of Health and Disease (DOHaD) hypothesis. The mechanism of “metabolic memory” has become a hot topic in the field of DM worldwide and could be a key to understanding the pathogenesis of DM. In recent years, several large cohort studies have shown that shift workers have a higher risk of developing type 2 diabetes mellitus (T2DM) and worse control of blood glucose levels. Furthermore, a maternal high-fat diet could lead to metabolic disorders and abnormal expression of clock genes and clock-controlled genes in offspring. Thus, disorders of circadian rhythm might play a pivotal role in glucose metabolic disturbances, especially in terms of early adverse nutritional environments and the development of metabolic diseases in later life. In addition, as a peripheral clock, the gut microbiota has its own circadian rhythm that fluctuates with periodic feeding and has been widely recognized for its significant role in metabolism. In light of the important roles of the gut microbiota and circadian clock in metabolic health and their interconnected regulatory relationship, we propose that the “gut microbiota-circadian clock axis” might be a novel and crucial mechanism to decipher “metabolic memory.” The “gut microbiota-circadian clock axis” is expected to facilitate the future development of a novel target for the prevention and intervention of diabetes during the early stage of life.

CORTISOL CIRCADIAN RHYTHM AND INSULIN RESISTANCE IN MUSCLE: EFFECT OF DOSING AND TIMING OF HYDROCORTISONE EXPOSURE ON INSULIN SENSITIVITY IN SYNCHRONIZED MUSCLE CELLS.

2020 ◽  
Author(s):  
Mariarosaria Negri ◽  
Claudia Pivonello ◽  
Chiara Simeoli ◽  
Gilda Di Gennaro ◽  
Mary Anna Venneri ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Circadian Rhythm ◽  
Insulin Sensitivity ◽  
Circadian Clock ◽  
Insulin Signaling ◽  
Clock Genes ◽  
Muscle Cells ◽  
C2c12 Cells ◽  
Circadian Expression

Introduction/Aim: Circadian rhythm disruption is emerging as a risk factor for metabolic disorders and particularly, alterations in clock genes circadian expression have been shown to influence insulin sensitivity. Recently, the reciprocal interplay between the circadian clock machinery and HPA axis has been largely demonstrated: the circadian clock may control the physiological circadian endogenous glucocorticoids secretion and action; glucocorticoids, in turn, are potent regulator of the circadian clock and their inappropriate replacement has been associated with metabolic impairment. The aim of the current study was to investigate in vitro the interaction between the timing-of-the-day exposure to different hydrocortisone (HC) concentrations on muscle insulin sensitivity. Methods: Serum-shock synchronized mouse skeletal muscle C2C12 cells were exposed to different HC concentrations recapitulating the circulating daily physiological cortisol profile (standard cortisol profile), the circulating daily cortisol profile that reached in adrenal insufficient (AI) patients treated with once-daily MR-HC (flat cortisol profile) and treated with thrice-daily of conventional IR-HC (steep cortisol profile). The 24 hrs spontaneous oscillation of the clock genes in synchronized C2C12 cells was used to align the timing for in vitro HC exposure (Bmal1 acrophase, midphase and bathyphase) with the reference times of cortisol peaks in AI treated with IR-HC (8 am, 1 pm, 6 pm). A panel of 84 insulin sensitivity related genes and intracellular insulin signaling proteins were analyzed by RT-qPCR and western blot, respectively. Results: Only the steep profile, characterized by a higher HC exposure during Bmal1 bathyphase, produced significant downregulation in 21 insulin sensitivity-related genes. Among these, Insr, Irs1, Irs2, Pi3kca and Adipor2 were downregulated when compared the flat to the standard or steep profile. Reduced intracellular IRS1 Tyr608, AKT Ser473, AMPK Thr172 and ACC Ser79 phosphorylations were also observed. Conclusions: The current study demonstrated that is late-in-the-day cortisol exposure that modulates insulin sensitivity-related genes expression and intracellular insulin signaling in skeletal muscle cells.

Modulatory effects of 5-fluorouracil on the rhythmic expression of circadian clock genes: A possible mechanism of chemotherapy-induced circadian rhythm disturbances

2008 ◽  
Vol 75 (8) ◽  
pp. 1616-1622 ◽  
Author(s):  
Hideyuki Terazono ◽  
Ahmed Hamdan ◽  
Naoya Matsunaga ◽  
Naoto Hayasaka ◽  
Hiroaki Kaji ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Circadian Clock ◽  
Clock Genes ◽  
Rhythmic Expression ◽  
Circadian Clock Genes

Enhanced effect of daytime restricted feeding on the circadian rhythm of streptozotocin-induced type 2 diabetic rats

2012 ◽  
Vol 302 (9) ◽  
pp. E1027-E1035 ◽  
Author(s):  
Tao Wu ◽  
Fen ZhuGe ◽  
Lu Sun ◽  
Yinhua Ni ◽  
Ou Fu ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Pineal Gland ◽  
Circadian Clock ◽  
Clock Genes ◽  
Activity Rhythm ◽  
Diabetic Rats ◽  
Restricted Feeding ◽  
Behavioral Rhythm ◽  
Type 2 Diabetic

There is increasing awareness of the link between impaired circadian clocks and multiple metabolic diseases. However, the impairment of the circadian clock by type 2 diabetes has not been fully elucidated. To understand whether and how the function of circadian clock is impaired under the diabetic condition, we examined not only the expression of circadian genes in the heart and pineal gland but also the behavioral rhythm of type 2 diabetic and control rats in both the nighttime restricted feeding (NRF) and daytime restricted feeding (DRF) conditions. In the NRF condition, the circadian expression of clock genes in the heart and pineal gland was conserved in the diabetic rats, being similar to that in the control rats. DRF shifted the circadian phases of peripheral clock genes more efficiently in the diabetic rats than those in the control rats. Moreover, the activity rhythm of rats in the diabetic group was completely shifted from the dark phase to the light phase after 5 days of DRF treatment, whereas the activity rhythm of rats in the control group was still under the control of the suprachiasmatic nucleus (SCN) after the same DRF treatment. Furthermore, the serum glucose rhythm of type 2 diabetic rats was also shifted and controlled by the external feeding schedule, ignoring the SCN rhythm. Therefore, DRF shows stronger effect on the reentrainment of circadian rhythm in the type 2 diabetic rats, suggesting that the circadian system in diabetes is unstable and more easily shifted by feeding stimuli.

scholarly journals Roles of Neuropeptides, VIP and AVP, in the Mammalian Central Circadian Clock

2021 ◽  
Vol 15 ◽  
Author(s):  
Daisuke Ono ◽  
Ken-ichi Honma ◽  
Sato Honma
Keyword(s):  
Transcription Factors ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Cellular Networks ◽  
Clock Genes ◽  
Circadian System ◽  
Developmental Changes ◽  
Circadian Period ◽  
Functional Roles ◽  
Environmental Light

In mammals, the central circadian clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Individual SCN cells exhibit intrinsic oscillations, and their circadian period and robustness are different cell by cell in the absence of cellular coupling, indicating that cellular coupling is important for coherent circadian rhythms in the SCN. Several neuropeptides such as arginine vasopressin (AVP) and vasoactive intestinal polypeptide (VIP) are expressed in the SCN, where these neuropeptides function as synchronizers and are important for entrainment to environmental light and for determining the circadian period. These neuropeptides are also related to developmental changes of the circadian system of the SCN. Transcription factors are required for the formation of neuropeptide-related neuronal networks. Although VIP is critical for synchrony of circadian rhythms in the neonatal SCN, it is not required for synchrony in the embryonic SCN. During postnatal development, the clock genes cryptochrome (Cry)1 and Cry2 are involved in the maturation of cellular networks, and AVP is involved in SCN networks. This mini-review focuses on the functional roles of neuropeptides in the SCN based on recent findings in the literature.

scholarly journals Regulation of the Hypothalamic-Pituitary-Adrenal Axis Circadian Rhythm by Endocannabinoids Is Sexually Diergic

2010 ◽  
Vol 95 (7) ◽  
pp. 3561-3561
Author(s):  
Helen C. Atkinson ◽  
James D. Leggett ◽  
Susan A. Wood ◽  
Emma S. Castrique ◽  
Yvonne M. Kershaw ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Hypothalamic Pituitary Adrenal Axis ◽  
Hypothalamic Pituitary Adrenal ◽  
Adrenal Axis ◽  
Pituitary Adrenal Axis
Sign in / Sign up

Export Citation Format

Share Document