Circadian Pattern Of Cortisol Research Articles

24 HOURS CHRONOMICS OF AMBULATORY BLOOD PRESSURE/HEART RATE IN TERMS OF ACROPHASE & HYPERBARIC INDEX IN NIGHT SHIFT NURSING PROFESSIONALS: RISK FOR CARDIOVASCULAR DISEASES

Objective: This study was aimed to investigate the effect of Light at night and Rotating night shift as risk factor for cardiovascular diseases. 24 hours chronomics of BP/HR in terms of Double amplitude, Acrophase and Hyperbaric index and its relation with circadian rhythm of salivary cortisol and 6 sulfatoxy melatonin levels in night shift nursing professional. Design and method: 56 night shift nurses, aged 20 to 40 years, performing day and night shift duties were recruited from the Trauma Center, KGMU, India, and 56 age sex matched actual day workers were also enrolled as controls. During their night and day shift duties, BP/HR were recorded by Ambulatory Blood Pressure Monitoring (ABPM) along with circadian pattern of cortisol in saliva, metalonin in urine also tested. Results: Highly significant difference was found in double amplitude (2DA) of among between night (23.10 ± 14.68) and day shift (34.27 ± 16.44) (p < 0.0005). In night shift, hyperbaric index (HBI) of mean SBP was found to be increased at 00 to 03 am (midnight) while during day shift, peak was found at 06 to 09 am. HBI of mean HR was found to be increased at 18 to 21 pm during night shift while in controls, peak was found at 09 to 12 & again 15 to 18 pm of SBP, DBP & HR. Alterations in Acrophase of BP/HR were very common among night shift workers and Ecphasia was found in few nights shift workers. Difference was found in night cortisol levels among night (4.08 ± 3.28) vs day shift (2.62 ± 2.37), while in comparison to night shift or day shift with controls (1.82 ± 1.18) these difference was significant (p < 0.05). Conclusions: Alteration in morning melatonin and Night cortisol level were found during night shift. Reverse pattern of Acrophase and HBI of BP/HR along with salivary cortisol during night shift represents desynchronization. It indicates that the circadian rhythm was disrupted during night shift and incomplete recovery occurs during day shift. It may leads to future cardio vascular diseases risk.

EFFECT OF ROTATING SHIFT WORK ON THE LEVEL OF SOME HORMONES AND QUALITY OF LIFE OF RESIDENT PHYSICIANS IN ZAGAZIG UNIVERSITY HOSPITALS

Introduction: Shift work is dividing working hours among two or more occupational groups in order to cover the time needed for duty performance or production process. Physicians participated in a shift-work environment since the early days of medicine. Shift work may alter the secretion levels and circadian pattern of cortisol, prolactin and melatonin. Night shift workers experience a variety of physical symptoms and adverse health effects especially those associated with gastrointestinal dysfunction, cardiovascular morbidity. Also shift work negatively affects quality of life. Aim of work: The current study aimed to assess the disturbances of the normal hormonal profile, quality of life and health status among rotating shift working resident physicians and evaluate the relationship between some occupational risk factors andthese disturbances. Materials and methods: The work was conducted on 50 rotating shift working resident physicians as exposed group, matched with 50 day only working resident physicians and demonstrators as non exposed group using a questionnaire including demographic data, occupational history, Gastrointestinal and Cardiovascular symptoms, Quality of life. Cortisol, prolactin, melatonin serum levels were measured. Results: The prolactin and cortisol showed a statistically significant increase while melatonin showed statistically significant decrease among rotating shift working resident physicians compared to the day-time working physicians. Also Quality of life was worse and GIT and Cardiovascular disorders were more frequent among rotating shift working resident physicians in contrast to those of day-shift. In correlation between hormones level and Cumulative working period, there was a statistically significant positive correlation with cortisol and prolactin and a statistically significant negative correlation with melatonin. Conclusion: The study reported that shift workers had disturbances in the normal hormonal profile, quality of life and health status andthese disturbances increased by high work load.

Effects of Fiber Supplementation for Four Weeks on Athletic Performance in Japanese College Athletes: A Case Study—Measurement of the Athletic Performance, Salivary Biomarkers of Stress, and Mood, Affect Balance

Aim: In this study, we explored the effects of dietary fiber on athletic performance. Methods: Twenty healthy college athletes (male/female, 1/1) consumed 6 grams of dietary fiber (Fiberpro, Taiyo Lab Inc., Tokyo) daily for four weeks and were evaluated for their athletic performance, salivary biomarkers of stress (α-amylase activity pre-post exercise, cortisol, melatonin, and secretory immunoglobulin A (SIgA) levels), and mood/affect using the Profile of Mood State 2nd edition (POMS 2®). Measurements were taken at baseline (before supplementation), at Week 4 (after 4 weeks of supplementation), and at Week 8 (4 weeks after the completion of supplementation). Results: Results showed that athletic performance and exercise-induced elevation in salivary α-amylase activity improved with Fiberpro supplementation in both men and women. Further, the Anger-Hostility scale in POMS was significantly elevated in men; in women, an increase in Vigor-Activity score, a single index of positive mood, was noted. These findings suggest that Fiberpro may induce differential affective responses in men and women. Meanwhile, Fiberpro did not affect the normal diurnal changes in salivary melatonin and SIgA levels, but it appeared to augment the normal circadian patterns of cortisol, an effect that persisted for a month without Fiberpro intake. We propose that boosting fiber intake in young, healthy athletes may improve gut microbiota and confer resilience against stress.

Minding the body: Psychotherapy and cancer survival

This article reviews evidence regarding effects of psychotherapy on overall cancer survival time. Special emphasis is given to research on adverse effects of depression on cancer survival, breast cancer, and mediating psychophysiological pathways linking psychosocial support to longer survival. It reviews all published clinical trials addressing effects of psychotherapy on cancer survival, emphasizing depression, breast cancer, and psychophysiological evidence linking stress, depression, and support to cancer survival. Systematic literature review and synthesis. Eight of 15 published trials indicate that psychotherapy enhances cancer survival time. No studies show an adverse effect of psychotherapy on cancer survival. Potential psychophysiological mechanisms linking stress to shorter survival include dysregulation of diurnal cortisol, increased pro-inflammatory cytokines, reduced natural killer cell activity, shorter telomeres and lower telomerase activity, glucocorticoid-mediated suppression of p53 and BrCA1 gene expression, and sympathetic nervous system activation of vascular endothelial growth factor. Stress and support affect the course of cancer progression. What is known? Stress and support have been thought to be related to cancer risk and progression, but evidence has been mixed. Depression is a natural co-morbid condition with cancer. It has not been clear how stress and support could physiologically affect the rate of cancer progression. Immune function was not thought to have much relevance to cancer progression. Few other physiological mechanisms linking stress to cancer progression were known. What does this paper add? There is evidence from 15 RCTs indicating that effective psychosocial support improves quantity as well as quality of life with cancer. There is evidence that chronic depression predicts poorer prognosis with cancer. Dysregulated circadian cortisol patterns predict more rapid cancer progression. Inflammatory processes affect cancer growth and progression. Sympathetic nervous system activity, telomere length, telomerase activity, and oncogene expression are affected by stress and can affect cancer growth.

Cortisol Awakening Response Is Linked to Disease Course and Progression in Multiple Sclerosis

ObjectivesDysregulation of the hypothalamus-pituitary-adrenal (HPA) axis has frequently been reported in multiple sclerosis (MS). So far, HPA axis function in MS has predominantly been studied under pharmacological stimulation which is associated with a series of methodological caveats. Knowledge of circadian cortisol patterns and cortisol awakening response (CAR) is still limited.MethodsA total of 77 MS patients (55 relapsing-remitting MS (RRMS)/22 secondary-progressive MS (SPMS)) as well as 34 healthy control (HC) subjects were enrolled. Diurnal cortisol release was assessed by repeated salivary cortisol sampling. Neurological disability was rated by the Kurtzke’s Expanded Disability Status Scale (EDSS). Depressive symptoms and perceived stress were assessed by self-report measures.ResultsRRMS but not SPMS patients differed in circadian cortisol release from HC subjects. Differences in cortisol release were restricted to CAR. Treated and treatment naïve RRMS patients did not differ in CAR. In a RRMS follow-up cohort (nine months follow-up), RRMS patients with EDSS progression (≥0.5) expressed a significantly greater CAR compared to HC subjects. RRMS patients with a stable EDSS did not differ from HC subjects. Neither depressive symptoms nor perceived stress ratings were associated with CAR in RRMS patients. In a step-wise regression analysis, EDSS at baseline and CAR were predictive of EDSS at follow-up (R2 = 67%) for RRMS patients.ConclusionsCircadian cortisol release, in particular CAR, shows a course specific pattern with most pronounced release in RRMS. There is also some evidence for greater CAR in RRMS patients with EDSS progression. As a consequence, CAR might be of predictive value in terms of neurological disability in RRMS patients. The possible role of neuroendocrine-immune interactions in MS pathogenesis is further discussed.

Basal, Circadian, and Acute Inflammation in Normal versus Overweight Men

Increased inflammation is present in obese compared with normal weight individuals, but inflammation characteristics of nonobese, overweight individuals are less clear. The objective of this study was to determine whether basal, circadian, and posteccentric exercise inflammation levels differ between normal and overweight men. Men (18-35 yr old) classified as normal weight (body mass index ≤25 kg·m, n = 20) and overweight (body mass index = 25-30 kg·m, n = 10) completed exercise (EX) and control (CON) conditions in random order. Maximal voluntary effort and eccentric actions (3 × 15) using the elbow flexor muscles of one arm were performed, and blood was collected preexercise and 4, 8, 12, and 24 h postexercise at 7:00 a.m., 12:00 p.m., 4:00 p.m., 8:00 p.m., and 7:00 a.m. Blood was collected on a time-matched schedule without exercise for CON. Soluble tumor necrosis factor receptor-1, interleukin-6, C-reactive protein (CRP), and cortisol responses (EX value - time-matched CON value) were measured. Basal CRP was higher in the overweight compared with normal weight group (mean ± SD, 0.542 ± 0.578 vs 1.395 ± 1.041 mg·L). Soluble tumor necrosis factor receptor-1 increased (P < 0.05) 8 h postexercise in both groups, and the response was greater 12 and 24 h postexercise in the overweight compared with normal weight groups. Interleukin-6 increased (P < 0.05) 8 h postexercise, with a trend (P = 0.09) to be greater in the overweight group. CRP and cortisol responses were not detected. The low-grade inflammation state in overweight compared with normal weight men includes both higher basal CRP concentrations and enhanced acute inflammation, but not in changes to the circadian patterns of cortisol and inflammation variables.

Replacement therapy of oral hydrocortisone in adrenal insufficiency: the influence of gastrointestinal factors

Background: Replacing glucocorticoids in primary adrenal insufficiency (AI) or Addison's disease (AD) is today based on oral replacement therapy with hydrocortisone in a conventional immediate-release tablet. It is recognised that physiological gastrointestinal factors may have a strong influence on the plasma concentration-time profile of hydrocortisone. Hydrocortisone has a sufficiently high permeability in both the small and large intestine, but in vivo dissolution from the available oral product is limited at higher doses. The short elimination half-life of hydrocortisone (∼ 1.5 h) when given in traditional immediate-release dosage forms requires two or more dose administrations per day, with high peaks and low trough values in between. The endogenous secretion of cortisol from the adrenal cortex follows a distinct diurnal pattern, with increasing and high plasma levels of cortisol early in the morning (∼ 05.00 – 08.00 h), intermediate levels in the afternoon, low levels in the evening and a cortisol-free interval at night. There is, therefore, a clinical need for an improved drug delivery product that more closely follows the circadian pattern of cortisol in plasma. Objective: The pharmaceutical and biopharmaceutical properties of the dosage form containing hydrocortisone will determine intestinal absorption rate and the plasma concentration-time profile of hydrocortisone (cortisol). Factors that cause or result in pharmacokinetic variability should be understood and avoided where possible. Methods: A literature search was performed with the aim of covering the field of gastrointestinal drug absorption of hydrocortisone in AD. Results/conclusion: Novel oral drug delivery principles for facilitation of once-daily dosing and providing a safe and physiologically based plasma concentration-time profile of hydrocortisone in replacement therapy are discussed. Development of new drug formulations is ongoing and will certainly lead to an improved replacement therapy of AD with hydrocortisone. Of special interest is a therapy based on once-daily treatment and less fluctuating plasma concentrations of hydrocortisone (cortisol).

Neuroendocrine (HPA axis) and clinical correlates during fluvoxamine and amitriptyline treatment

The effect of amitriptyline on hypothalamic–pituitary–adrenocortical (HPA) axis activity was compared with that of fluvoxamine in 38 patients suffering from DMS-IV major depressive disorder. Basal plasma adrenocorticotropic hormone and cortisol levels were determined in the so-called “observation window” of an hour (08:00–09:00 h), and cortisol levels were determined again at 20:00 h. Clinical and biochemical assessments were performed before therapy ( T 0), at day 14 ( T 14), and at day 42 ( T 42) of the course of antidepressant treatment. At T 0, neuroendocrine parameters did not differ in patients from those in controls, except for the ratio between cortisol levels at 20:00 h and the mean level of the “window” (ratio F 20/F 8), which was significantly higher, suggesting a dysregulation of the circadian pattern of cortisol. Although a decrease in the ratio F 20/F 8 was already apparent at T 14 of both treatments, the repeated measures analysis of variance failed to demonstrate a significant variation with time ( T 0, T 14, and T 42) and with treatment (amitriptyline and fluvoxamine) for any hormonal measure. At T 42, both treated groups showed a similar level of clinical improvement. Our results did not demonstrate any effect of antidepressant therapy on the cortisol circadian rhythm abnormality.

Diurnal patterns of cortisol and thyroid hormones in the Harbor seal ( Phoca vitulina) during summer and winter seasons

A leading hypothesis for the dramatic population decline of the Alaskan harbor seal over the last 2–3 decades have related environmental changes to a decrease in the quality or quantity of available prey. If harbor seals are experiencing some sort of nutritional stress, it is important to understand the physiological and endocrine mechanisms controlling metabolic homeostasis in this species. The purpose of this research project was to determine whether circadian patterns of cortisol and total and free thyroxine (T 4) and triiodothyronine (T 3) are present in the harbor seal during the summer and winter seasons, and identify how they might alter metabolic rate and maintenance of body reserves. This study was carried out at the Alaska SeaLife Center in Seward, Alaska in June 2000 and January 2001. Blood samples were obtained every 2–3 h over a 24-h period through in-dwelling catheters inserted the day before sampling. The presence of a diurnal rhythm was determined by comparing levels between ante meridian (12 am to noon) and post meridian (noon to 12 midnight) time periods. Mean daily cortisol concentrations were not significantly different between seasons, but cortisol displayed a circadian rhythm only during the summer. Mean concentrations of cortisol (51.5 ng/ml ± 20.3) in the summer hours of ante meridian differed significantly from levels in the hours of post meridian (28.5 ng/ml ± 17.4). Neither total and free T 4, nor T 3, displayed a diurnal rhythm in either season. However, tT 4, tT 3, and fT 3 levels were significantly higher in the winter than in the summer. There was no seasonal effect on fT 4 levels. The absence of a circadian rhythm of cortisol during the winter may have been a result of the limited amount of daylight as well as the continual need to produce metabolic heat as a by-product of gluconeogenesis. Higher levels of thyroid hormones in the winter indicate an adaptive mechanism to cope with the low temperatures of winter.

Sleep and the hypothalamo-pituitary-adrenocortical system.

The intention of this review is to summarize the current knowledge on the bidirectional interaction between sleep EEG and the secretion of corticotropin (ACTH) and cortisol. The administration of various hypothalamic-pituitary- adrenocortical (HPA) hormones and their antagonists exerts specific sleep-EEG changes in several species including humans. It is well documented that corticotropin releasing hormone (CRH) impairs sleep and enhances vigilance. In addition, it may promote REM sleep. Changes in the growth hormone-releasing hormone (GHRH):CRH ratio in favour of CRH appear to contribute to shallow sleep, elevated cortisol levels and blunted GH in depression and ageing. On the other hand, in women GHRH appears to exert CRH-like effects on sleep. Acute cortisol administration increases slow-wave sleep (SWS) and GH, probably due to feedback inhibition of CRH, and inhibits REM sleep. With the mixed glucocorticoid and progesterone receptor antagonist mifepriston sleep is disrupted. Subchronic administration of the glucocorticoid agonist methylprednisolone desinhibited REM sleep. A synergism of elevated CRH and cortisol activity may contribute to REM disinhibition during depression. Also ACTH and vasopressin modulate sleep specifically but their physiological role remains unclear. For example acute icv vasopressin enhances wakefulness in rats, whereas its long-term administration increases SWS in the elderly. In various studies the interaction of sleep EEG and HPA hormones has been investigated at the baseline, after manipulation of sleep-wake behaviour and after environmental changes. Most studies agree that the circadian pattern of cortisol is relatively independent from sleep and environmental influences. Some data suggest a major effect of light on cortisol secretion. Sleeping is widely associated with blunting and awakenings are linked with increases of HPA hormones.

Longitudinal evaluation of the development of salivary cortisol circadian rhythm in infancy.

Although an outstanding characteristic of the adrenocortical function of children and adults is its circadian rhythm, little information is available about the age of appearance of such rhythm in infancy. The main obstacle has been the ethical difficulty in obtaining serial blood samples from healthy infants. We monitored the development of cortisol daily rhythm using noninvasive salivary cortisol determination. A longitudinal study of a group of 9 healthy infants was performed. Salivary samples were obtained in the morning, afternoon and night at 2, 4, 8, 12, 16, 20 and 24 post-natal weeks from all infants. Cortisol was determined by RIA in 25-microl salivary samples. Two techniques based on assay coefficients of variation were employed to characterize a normal circadian pattern of cortisol. Five infants (55%) established and maintained their cortisol rhythm as early as at 2, 4 and 8 weeks of age. In the remaining 4 infants the age of appearance was 12 and 20 weeks. This rhythm emerged in the group as a whole at a mean age of 8 weeks. Our data suggest that, in most normal infants, the development of hypothalamic-pituitary-adrenal axis circadian maturation may occur at a much earlier age than previously described.

Circadian patterns of cortisol, prolactin, and growth hormonal secretion during bingeing and vomiting in normal weight bulimic patients

Women who are of normal weight and have bulimia nervosa exhibit multiple neuroendocrine disturbances. We hypothesized that bingeing and vomiting behavior could be contributory because food consumption in healthy volunteers increases plasma cortisol and prolactin secretion and suppresses growth hormone secretion. Thus, we investigated the effects of bingeing and vomiting on the circadian pattern (measurements every 20 min for 24 hr) of these hormones in comparison to healthy control women eating normally. Bingeing and vomiting were associated with modest increases in cortisol and prolactin and reductions in growth hormone secretion. However, this bingeing or purging did not alter mean 24-hr pattern of cortisol and growth hormone secretion as values for bulimics were similar to controls. While mean daytime patterns of prolactin secretion were similar in bulimics and controls, bulimic patients had a significant reduction of nocturnal prolactin levels. In summary, bingeing and vomiting does not appear to have a substantial influence on hormonal secretion. However, bulimic women have blunted nocturnal prolactin patterns.

Influence of the gonads on cortisol secretion in female rhesus macaques.

Circadian and ultradian patterns of plasma cortisol were assessed in four intact female rhesus macaques during both the late follicular (days 9-10) and midluteal (days 21-22) phases of the menstrual cycle and compared to patterns in four ovariectomized macaques. Blood samples were drawn from a remote site at 15-min intervals for 24 h via an indwelling catheter. Measures of estrogen and progesterone were obtained for each subject. For purposes of data analyses, group cortisol measurements were collapsed across hourly intervals and submitted to analysis of variance. Pulsatile characteristics of cortisol release were determined for each subject using the PULSAR computer program. Circadian cortisol patterns, present in all three groups, were characterized by a progressive rise during early morning hours (0300-0600 h), followed by a decline of short duration. All groups then displayed an unexpected midday peak (0900-1400 h), at which time cortisol levels reached their daily zenith. In each of the three groups, cortisol levels reached a nadir during late afternoon hours shortly after the light phase ended. The amplitude of circadian changes and daily mean levels of cortisol were significantly reduced by ovariectomy, without alterations in pulsatile characteristics of cortisol secretion. Daily mean cortisol levels decreased from approximately 8 micrograms/100 ml in intact subjects to 4.5 micrograms/100 ml after ovariectomy. No significant differences in the circadian/ultradian periodicity of cortisol secretion were detected between the follicular and luteal groups. When data in the intact female groups were combined and compared to those previously obtained from gonadally intact adult male macaques, similar 24-h patterns of cortisol secretion were detected. Surprisingly, amplitude changes in cortisol concentrations after ovariectomy were temporally and quantitatively similar to those in orchidectomized males. In both male and female animals, circadian patterns of cortisol secretion were reduced by gonadectomy. These results are discussed in terms of the activational influence of gonadal steroids on hypothalamic-pituitary-adrenocortical function.

Diurnal Patterns and Regulation of Cortisol Secretion in Pregnancy*

Plasma concentrations of cortisol and corticosteroid-binding globulin are elevated substantially in pregnancy; only the free cortisol fraction is biologically active. Previous suggestions that plasma free cortisol increased above nongravid levels in pregnancy were difficult to reconcile with the absence of manifestations of hypercortisolism. Furthermore, any such elevation should be associated with some alteration in the regulation of cortisol secretion. Therefore, the physiology of cortisol secretion was studied by measuring plasma cortisol at 20-min intervals for 24 h. Free cortisol levels were evaluated by determining the plasma free cortisol index and the rate of urinary cortisol excretion. Circadian cortisol patterns in pregnant and nonpregnant subjects were virtually identical, but total plasma cortisol was significantly higher in pregnancy. Calculated plasma biological half-lives and production rates of cortisol were increased significantly in gravidas (t½: pregnant, 104.6 min; nonpregnant, 69.5 min; daily production rate: pregnant, 28.0 mg; nonpregnant, 11.2 mg). Such increases should produce rises in plasma free cortisol, an assumption supported by finding elevations of the free cortisol index in gravidas at 0800 and 2400 h (pregnant, 14.9 ± 1.9 and 3.3 ± 0.2; nonpregnant, 4.0 ± 0.6 and 1.2 ± 0.3) and elevations of the 24-h urinary cortisol excretion rate. Normal circadian rhythmicity despite elevated free cortisol suggests that maternal hypothalamic-pituitary regulation is altered. Resetting of feedback and lack of manifestations of hypercortisolism could be explained by tissue refractoriness to the effects of cortisol in pregnancy.

Circadian Cortisol Secretory Rhythms in Cushing's Disease*

Plasma cortisol was measured at 20-min intervals for 24 h in eight patients with Cushing's disease and ACTH-secreting pituitary tumors. The 24-h mean (+/- SD) cortisol level was 25.6 +/- 11.3 microgram/dl (range, 15.5--40.6), which was significantly higher than the level of normal control subjects (P less than 0.01). The 24-h mean ACTH level varied between 22--107 pg/ml, with a mean +/- SD of 63.4 +/- 27.2. The mean ACTH level was higher than that of the control subjects but the difference was not statistically significant. The 24-h cortisol secretory pattern was characterized by an absence of the normal circadian variation and a failure of the plasma cortisol level to fall to less than 2 microgram/dl between 2300--0300 h. The coefficient of variation, an expression of the amplitude of cortisol secretory episodes, was significantly decreased in patients with Cushing's disease compared to normal control subjects; there was no significant difference in the number of cortisol secretory episodes in the patients vs. control subjects. Three of the patients were restudied after successful resection of their ACTH-secreting pituitary tumors. Two showed normalization of their 24-h circadian cortisol patterns and normal metyrapone responses. In the third, the 24-h mean cortisol level was normal, but the circadian cortisol rhythm remained abnormal. This patient had diminished ACTH reserve, demonstrated by a subnormal response to metyrapone. Additional studies will be required to determine if normalization of the circadian cortisol rhythm occurs in all patients with Cushing's disease who are cured after transsphenoidal microsurgery and who also show normal ACTH reserve.