The emerging importance of ultradian glucocorticoid rhythms within metabolic pathology

Flynn, Benjamin P.; Conway-Campbell, Becky; Lightman, Stafford

doi:10.1016/j.ando.2018.03.003

Cited by 11 publications

(8 citation statements)

References 15 publications

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“…It has long been known that stress and GCs regulate metabolic [ 178 , 179 ] immunological [ 180 ] and cognitive processes [ 181 , 182 ] throughout the body and brain. Of particular relevance to the subject of this review, are the vast number of stress and GC-dependent effects on metabolism and energy balance, reviewed in [ 183 , 184 ].…”

Section: Gc Regulation Of Metabolism and Feeding Behaviormentioning

confidence: 99%

Arginine vasopressin: Direct and indirect action on metabolism

2021

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Section: Gc Regulation Of Metabolism and Feeding Behaviormentioning

confidence: 99%

Arginine vasopressin: Direct and indirect action on metabolism

2021

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“…On the positive side, in the 5-min data-set, the accuracy of the sampling times relative to awakening, so crucial to the detailed examination of process and timing within the CAR, leads to confidence in the results reported. Also, given an established knowledge base on the periodicity of the ultradian rhythm and the pulsatile nature of cortisol secretion (Flynn et al, 2018;Trifonova et al,2013;Lightman and Conway-Campbell, 2010;Veldhuis et al, 1989), it would frankly have been surprising if the evidence adduced here to show their foot-prints in the 5-min data had not been forthcoming. These foot-prints were the basis for subsequent analyses of individual peak to trough amplitude (PTA) estimates as potential indicators of CAR salience as a secretory signal.…”

Section: Discussionmentioning

confidence: 92%

“…Yet secretion occurs in large ultradian bursts, at roughly hourly intervals, with little activity between them. Pulsatile delivery is necessary for efficient HPA axis signalling (Flynn et al, 2018;Lightman and Conway-Campbell, 2010). The possible functional significance of CAR secretion 'shapes', as salient signals reflecting the pulsatile nature of secretion, has largely prompted these investigations Typically, pulsatility is studied using continuous blood sampling.…”

Section: Introductionmentioning

confidence: 99%

Salience versus magnitude in the measurement of the cortisol awakening response

Evans

Thorn

Hucklebridge

et al. 2019

Psychoneuroendocrinology

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Pulsatile ultradian secretion of cortisol, rarely studied in salivary data, has functional importance in hypothalamic pituitary adrenal (HPA) axis regulation. The first daily ultradian episode, the cortisol awakening response (CAR), was examined in healthy adults, in 5-min secretion rates of salivary cortisol from electronically monitored awakening time to 1.25h. Aggregated rates revealed a cubic trend, with wavelength of almost exactly 1h, as predicted from known ultradian periodicity. Peak secretion rate occurred 20-min post-awakening. Peak (20-min) to trough (59-min) amplitude (PTA) expressed a salient signal shape. Rates rose steeply to and from peak, and major secretion was packaged into a few 5-min intervals, inconsistent with normal or uniform distribution of 5-min rates, but consistent with known pulsatile cortisol delivery. Null hypotheses asserting normal or uniform distributions were rejected. Maximal rates overwhelmingly occurred before and minimal rates after 30-mins, with degree of extremity at each polarity significantly positively correlated. To demonstrate utility and reliability of PTA estimation in a clinically relevant domain, reanalyses of a previously published study were conducted. Data from only three saliva samples were used, given importance of cost considerations for many CAR researchers. Difference between mean rates before and after 30-min yielded a simple salience index, highly correlated with PTA derived from full 5-min interval data. CAR salience performed significantly better than traditional AUCi magnitude in discriminating control cases (higher inferred amplitude) and cases with Seasonal Affective Disorder (lower inferred amplitude). Evidence suggested that low AUCi may be more sensitive in identifying within-subject changes (e.g. more depressed mood in winter among SAD cases) and low CAR salience better at revealing enduring between-subjects associations (e.g. underlying disorder vulnerability). Since both PTA salience and AUCi magnitude can be analysed and compared using exactly the same data from the same commonly used saliva sampling points, further research is warranted into the importance of individual differences in patterns of cortisol delivery, not just how much is delivered.

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“…However, there is a body of literature indicating that it is not the absolute levels of corticosterone that play a role, but instead it is the rise and fall that matters. In this regard, Lightman and Conway-Campbell elegantly review the function of the HPA axis and show that the HPA-response to noise exposure (as a stressor), which increases circulating corticosterone, depends on whether the exposure occurs on the rising slope (facilitated HPA response) or the descending slope (suppressed HPA response), rather than the absolute levels of corticosterone (Flynn et al, 2018). Thus, the contribution of glucocorticoids on auditory function is likely a matter of dose, time, and duration.…”

Section: Bridging the Circadian Inflammation And Glucocorticoid Actimentioning

confidence: 99%

Circadian integration of inflammation and glucocorticoid actions: Implications for the cochlea

et al. 2019

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Auditory function has been shown to be influenced by the circadian system. Increasing evidence point towards the regulation of inflammation and glucocorticoid actions by circadian rhythms in the cochlea. Yet, how these three systems (circadian, immune and endocrine) converge to control auditory function remains to be established. Here we review the knowledge on immune and glucocorticoid actions, and how they interact with the circadian and the auditory system, with a particular emphasis on cochlear responses to noise trauma. We propose a multimodal approach to understand the mechanisms of noise-induced hearing loss by integrating the circadian, immune and endocrine systems into the bearings of the cochlea. Considering the well-established positive impact of chronotherapeutic approaches in the treatment of cardiovascular, asthma and cancer, an increased knowledge on the mechanisms where circadian, immune and glucocorticoids meet in the cochlea may improve current treatments against hearing disorders.

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The emerging importance of ultradian glucocorticoid rhythms within metabolic pathology

Cited by 11 publications

References 15 publications

Arginine vasopressin: Direct and indirect action on metabolism

Arginine vasopressin: Direct and indirect action on metabolism

Salience versus magnitude in the measurement of the cortisol awakening response

Circadian integration of inflammation and glucocorticoid actions: Implications for the cochlea

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