Cortisol Production Rate Research Articles

Daily Glucocorticoid Replacement Dose in Adrenal Insufficiency, a Mini Review.

The Endocrine Society Guidelines and recent reviews of adrenal insufficiency (AI) recommend a daily glucocorticoid replacement dose of 15 to 25 mg with a midpoint of 20 mg of hydrocortisone (HC) (alternatively 3 to 5 mg prednisolone) in divided doses in otherwise healthy individuals with AI. In contrast, a daily glucocorticoid replacement dose of 4.3 to 26 mg/d HC with a midpoint of 15 mg/d is predicted from current measurements of daily cortisol production rates and oral HC bioavailability. The higher HC doses recommended in the current guidelines may result in glucocorticoid overtreatment of some AI patients and associated long-term adverse outcomes. A titration method for determination of the individual patient’s daily glucocorticoid replacement dose and the impact of lower doses are reviewed. Future related research questions are identified.

Empiric Determination of the Daily Glucocorticoid Replacement Dose in Adrenal Insufficiency.

BackgroundFor the treatment of adrenal insufficiency (AI) in adults, the Endocrine Society’s recommended daily glucocorticoid replacement dose (DGRD) is 15 to 25 mg hydrocortisone (HC), which is approximately 1.7 times the reported mean daily cortisol production rate. Prolonged glucocorticoid overtreatment causes multiple morbidities.HypothesisWe tested the hypotheses that the DGRD, empirically determined by individual patient titration, is lower than that of the Endocrine Society guidelines and tolerated without evidence of glucocorticoid under-replacement.MethodsWe empirically determined the DGRD in 25 otherwise healthy adults with AI by titrating the DGRD to the lowest dose tolerated as judged by body mass index, blood pressure, serum sodium concentration and AI symptoms. Patients received either HC or prednisone (PRED). The HC equivalent of PRED was assumed to be 4:1.ResultsThe mean empirically determined DGRD, expressed as HC equivalent, was significantly less than the midpoint of the Endocrine Society’s recommended DGRD (7.6 ± 3.5 mg/m2 vs 11.8 mg/m2; P < 0.001). The DGRD in the adrenalectomy group was not significantly different than the DGRD of those with other AI causes (7.9 ± 4.0 mg/m2 vs 7.3 ± 3.1 mg/m2; P = ns), demonstrating that the empirically determined DGRD was not biased by residual cortisol secretion. There was no evidence of glucocorticoid under-replacement as determined by measured biometrics and AI symptoms.ConclusionsWe conclude that an empirically determined DGRD is significantly lower than that of the Endocrine Society guidelines and tolerated without evidence of glucocorticoid under-replacement.

An integrated PK-PD model for cortisol and the 17-hydroxyprogesterone and androstenedione biomarkers in children with congenital adrenal hyperplasia.

AimsThe aim of this study was to characterize the pharmacokinetic/pharmacodynamic relationships of cortisol and the adrenal biomarkers 17‐hydroxyprogesterone and androstenedione in children with congenital adrenal hyperplasia (CAH).MethodsA nonlinear mixed‐effect modelling approach was used to analyse cortisol, 17‐hydroxyprogesterone and androstenedione concentrations obtained over 6 hours from children with CAH (n = 50). A circadian rhythm was evident and the model leveraged literature information on circadian rhythm in untreated children with CAH. Indirect response models were applied in which cortisol inhibited the production rate of all three compounds using an I max model.ResultsCortisol was characterized by a one‐compartment model with apparent clearance and volume of distribution estimated at 22.9 L/h/70 kg and 41.1 L/70 kg, respectively. The IC50 values of cortisol concentrations for cortisol, 17‐hydroxyprogesterone and androstenedione were estimated to be 1.36, 0.45 and 0.75 μg/dL, respectively. The inhibitory effect was found to be more potent on 17OHP than D4A, and the IC50 values were higher in salt‐wasting subjects than simple virilizers. Production rates of cortisol, 17‐hydroxyprogesterone and androstenedione were higher in simple‐virilizer subjects. Half‐lives of cortisol, 17‐hydroxyprogesterone and androstenedione were 60, 47 and 77 minutes, respectively.ConclusionRapidly changing biomarker responses to cortisol concentrations highlight that single measurements provide volatile information about a child's disease control. Our model closely captured observed cortisol, 17‐hydroxyprogesterone and androstenedione concentrations. It can be used to predict concentrations over 24 hours and allows many novel exposure metrics to be calculated, e.g., AUC, AUC‐above‐threshold, time‐within‐range, etc. Our long‐range goal is to uncover dose–exposure–outcome relationships that clinicians can use in adjusting hydrocortisone dose and timing.

SAT-741 Salivary Cortisol and Cortisone Measurement Provide a Novel and Non-Invasive Method of Monitoring Medical Therapy in Cushing’s Syndrome

Introduction:Salivary glucocorticoids (cortisol [SalF], cortisone [SalE]) are collected non-invasively, unaffected by variation in cortisol binding globulin (CBG) and an established tool in the investigation of Cushing’s syndrome (CS). We have previously shown a strong correlation between salivary glucocorticoids and circulating free serum cortisol, better than that with total serum cortisol. Measurement by liquid chromatography with tandem mass spectrometry (LC-MS/MS) permits lower limits of quantification, eliminates cross-reactivity both between cortisol and cortisone, and by metyrapone-induced elevations in 11-deoxycortisol.Previous studies in CS have demonstrated that a mean (based on 5 samples during a single day) serum cortisol (serumF) of 150-300 nmol/l equates to a normal isotopically calculated cortisol production rate. We report the use of salivary glucocorticoid measurement in metyrapone-treated CS patients undergoing dose titration to achieve a mean serumF of 150-300 nmol/L.Methods:Seventeen (11 females; age-range 24-74 years) patients with CS undergoing dose titration with metyrapone were studied on 44 occasions: 15 ACTH-dependent (5 ectopic) and 2 adrenal.24 healthy male volunteers (HV) were also studied.Both cohorts had paired serumF and SalE and SalF samples collected at 5 time-points (10:00; 11:30; 13:00; 14:30; 16:00).Serum and salivary glucocorticoids were measured using LC-MS/MS.The TR for salivary glucocorticoids was determined from the mean SalE and SalF in HV whose mean serumF (n=20) was in the desired range (150-300 nmol/L). In CS patients the metyrapone dose had been titrated to achieve a mean serumF of 150-300 nmol/L on 14 (out of 44) occasions.Results:Mean SalE (r=0.70; p<0.001) and mean SalF (r=0.51; p<0.001) showed a significant correlation with serumF. The TR from HV for mean SalE and mean SalF were 5.8–24.7 nmol/L and 0.6-5.4 nmol/L respectively.In CS patients, SalE had greater sensitivity (79% vs. 75%) and specificity (80% vs. 57%) in predicting a mean serumF in the TR than SalF.Conclusion:We have demonstrated a close correlation between mean SalE and mean serumF in metyrapone treated CS patients. Salivary glucocorticoids within the derived TR were highly predictive for a target serumF. It is unsurprising, due to the effect of CBG on serumF measurements, that the sensitivity and specificity of SalE and SalF are not greater than reported. Consequently, SalE and SalF, as surrogates for free serum F, have the potential to be superior than serumF when assessing adequacy of medical therapy in CS and may permit out-of-hospital monitoring. Further work is required to validate these findings.

Heritability of Cortisol Production and Metabolism Throughout Adolescence.

ContextInter-individual differences in cortisol production and metabolism emerge with age and may be explained by genetic factors.ObjectiveTo estimate the relative contributions of genetic and environmental factors to inter-individual differences in cortisol production and metabolism throughout adolescence.DesignProspective follow-up study of twins.SettingNationwide register.Participants218 mono- and dizygotic twins (N = 109 pairs) born between 1995 amd 1996, recruited from the Netherlands Twin Register. Cortisol metabolites were determined in 213, 169, and 160 urine samples at the ages of 9, 12, and 17, respectively.Main outcome measuresThe total contribution of genetic factors (broad-sense heritability) and shared and unshared environmental influences to inter-individual differences in cortisol production and activities of 5α-reductase, 5β-reductase, and 11β-hydroxysteroid dehydrogenases and cytochrome P450 3A4.ResultsFor cortisol production rate at the ages of 9, 12, and 17, broad-sense heritability was estimated as 42%, 30%, and 0%, respectively, and the remainder of the variance was explained by unshared environmental factors. For cortisol metabolism indices, the following heritability was observed: for the A-ring reductases (5α-and 5β-reductases), broad-sense heritability increased with age (to >50%), while for the other indices (renal 11β-HSD2, global 11β-HSD, and CYP3A4), the contribution of genetic factors was highest (68%, 18%, and 67%, respectively) at age 12.ConclusionsThe contribution of genetic factors to inter-individual differences in cortisol production decreased between 12 and 17y, indicative of a predominant role of individual circumstances. For cortisol metabolism, distinct patterns of genetic and environmental influences were observed, with heritability that either increased with age or peaked at age 12y.

SAT-020 Empiric Determination of Daily Glucocorticoid Replacement Doses in Adrenal Insufficiency

Background: The Endocrine Society’s recommended adult daily glucocorticoid replacement dose (DGRD) for adrenal insufficiency (AI) is 15-25 mg cortisol/d. Adjusted for body surface area (BSA), the midpoint is 11.1 mg cortisol/m2/d. This is 1.6 times the reported mean daily cortisol production rate (FPR) of 7.0 mg/m2/d (range = 2.7-14). Prolonged glucocorticoid over-treatment may cause osteoporosis, diabetes, hypertension and immune suppression. Hypothesis. We tested the hypothesis that a carefully titrated DGRD would approximate the reported FPR without clinically adverse effects. Methods: We empirically determined the DGRD in 22 otherwise healthy adults with AI (17 primary, 5 secondary; 16 women, 6 men) by titrating the DGRD to the lowest dose tolerated as judged by BMI, BP, serum sodium concentration and AI symptoms. Patients received either hydrocortisone (HC) or prednisone. The HC equivalence of prednisone was assumed to be 4 to 1. P < 0.01 was considered statistically significant. BSA was calculated by the Mosteller formula and the Schlich formula that accounts for gender. Results. The DGRD (mean ± SD), expressed as HC equivalent dose and adjusted for BSA (Mosteller formula), was 7.6 ± 3.7 mg/m2/d (range 2.0-14.3). This closely approximated the reported mean FPR of 7.0 mg/m2/d, and was significantly (p < 0.01) less than the midpoint of the Endocrine Society’s recommended DGRD (11.1 mg/m2/d). As with the reported FPR there was a trend of DGRD/BSA to correlate with age (r2 = 0.20; p = 0.03). To be certain that the DGRD was not biased by residual cortisol secretion, we compared the DGRD in the 11 patients who had undergone bilateral adrenalectomy to those with other AI causes. The DGRD in the adrenalectomy group was 7.8 ± 4.2 mg/m2/d and was not significantly different than the DGRD of those with other AI causes (7.4 ± 3.3 mg/m2/d). We looked for evidence of over and under replacement by examining the correlation DGRD with BMI, BP, and serum sodium concentration. There were no significant positive correlations. Five patients had minimal hyponatremia with the lowest value being 135 mmol/L (lower nl limit = 137 mmol/L). There was a significant negative correlation of BMI with DGRD/BSA (r2 = 0.33; p = 0.005), indicating that obesity was not caused by over replacement, and that individuals with endogenous obesity maintained an elevated BMI on a low DGRD. When using the Schlich BSA formula to account for gender, no statistical differences or correlations were altered. Summary: The empirically determined DGRD closely approximated the reported FPR, was significantly lower than the currently recommended DGRD, and was without adverse side effects. Conclusion. A DGRD that is equivalent to FPR, but lower than the Endocrine Society’s DGRD, is adequate for most otherwise healthy patients with AI.

Prenatal maternal stress is associated with lower cortisol and cortisone levels in the first morning urine of 45-month-old children

Prenatal stress (PS) has been related to altered hypothalamic-pituitary-adrenal (HPA) axis activity later in life. So far, studies in children assessing HPA axis functioning have focused on salivary cortisol, reflecting daytime activity. The present work is part of a prospective study and aims to extend knowledge about the association between PS and HPA axis regulation in children.To do so, we investigated cortisol, cortisone, and the ratio cortisone/(cortisone + cortisol) in the first morning urine of 45-month-old children in relation to several measures of maternal stress during pregnancy. Urinary cortisol and cortisone were measured by online turbulent flow chromatography coupled with high performance liquid chromatography-tandem mass spectrometry. PS was defined as: perceived stress for aim 1 (Perceived Stress Scale; n = 280); presence of self-reported (n = 371) and expert-rated psychopathology for aim 2 (Mini International Neuropsychiatric Interview; n = 281); continuous measures of anxiety and depression for exploratory aim 3 (State-Trait Anxiety Inventory and Edinburgh Postnatal Depression Scale; n = 280).Aim 1: Perceived maternal PS showed negative associations with cortisol and cortisone levels. Aim 2: The presence of expert-rated maternal psychopathology was associated with reduced morning cortisone. Aim 3: Continuous measures of anxiety and depression showed negative associations with cortisol and cortisone levels. After correcting for multiple testing, perceived maternal PS (aim 1) and prenatal level of anxiety (aim 3) were significant predictors of children’s urinary cortisol and cortisone in the morning (and, in the case of cortisone, also prenatal level of depression).The ratio cortisone/(cortisone + cortisol) as a global marker for the balance between the enzymes metabolizing cortisol to cortisone and vice versa (11β-hydroxysteroid dehydrogenases type 1 and 2; 11β-HSD1 and 2) was not associated with any measure of maternal PS (aims 1–3).The present study provides insight into possible programming effects of PS on nocturnal HPA axis activity and a proxy of 11β-HSD in a large sample. The results suggest that the nocturnal rate of cortisol production is lower in children exposed to PS, but do not support the hypothesis of divergent 11β-HSD activity.

Clinical Outcomes of Minimized Hydrocortisone Dosage of 100 Mg/Day on Lower Occurrence of Hyperglycemia in Septic Shock Patients.

The current international guideline recommended 200 mg/day of hydrocortisone intravenously to treat septic shock. However, a subsequent study on cortisol metabolism actually showed an increase in cortisol level during sepsis. Hence, the smaller hydrocortisone dose of 100 mg/day might be sufficient and reduce steroid-associated complications. We aimed to compare the clinical outcomes of minimized hydrocortisone dose of 100 mg to the currently recommended dose in the treatment of septic shock patients. A double-blinded randomized controlled trial included 80 septic shock patients with hemodynamic instability despite fluid and vasopressive therapy. Participants were divided equally into two groups to treat with 100 mg/day or 200 mg/day of hydrocortisone, then stepwise down titrated and discontinued on day 8. The outcome of interest was the hyperglycemic rate. Vital status, time to shock reversal, superinfection and gastrointestinal bleeding rates were also compared. Patients with 100 mg hydrocortisone had significantly lower hyperglycemic rate compared with 200 mg, 63.9% versus 86.5% (the adjusted hazard ratio [HR], 0.08; 95% confidence interval [CI], 0.02-0.41, P = 0.002). Time to shock reversal was shorter in patients with 100 mg hydrocortisone, 2 days vs. 4 days, P = 0.031. The 28-day mortality rate when adjusted for Simplified Acute Physiology Score II showed no significant difference (HR, 0.68; 95% CI, 0.37-1.24, P = 0.209). The reinfection and gastrointestinal bleeding rates were comparable between groups. Minimized daily hydrocortisone dosage of 100 mg could lower the occurrence of hyperglycemia without increasing mortality in septic shock, compared with the currently recommended dosage of 200 mg/day.

Prednisolone is associated with a worse bone mineral density in primary adrenal insufficiency.

ContextPatients with primary adrenal insufficiency (PAI) or congenital adrenal hyperplasia (CAH) receive life-long glucocorticoid (GC) therapy. Daily GC doses are often above the physiological cortisol production rate and can cause long-term morbidities such as osteoporosis. No prospective trial has investigated the long-term effect of different GC therapies on bone mineral density (BMD) in those patients.ObjectivesTo determine if patients on hydrocortisone (HC) or prednisolone show changes in BMD after follow-up of 5.5 years. To investigate if BMD is altered after switching from immediate- to modified-release HC.Design and patientsProspective, observational, longitudinal study with evaluation of BMD by DXA at visit1, after 2.2 ± 0.4 (visit2) and after 5.5 ± 0.8 years (visit3) included 36 PAI and 8 CAH patients. Thirteen patients received prednisolone (age 52.5 ± 14.8 years; 8 women) and 31 patients received immediate-release HC (age 48.9 ± 15.8 years; 22 women). Twelve patients on immediate-release switched to modified-release HC at visit2.ResultsPrednisolone showed significantly lower Z-scores compared to HC at femoral neck (−0.85 ± 0.80 vs −0.25 ± 1.16, P < 0.05), trochanter (−0.96 ± 0.62 vs 0.51 ± 1.07, P < 0.05) and total hip (−0.78 ± 0.55 vs 0.36 ± 1.04, P < 0.05), but not at lumbar spine, throughout the study. Prednisolone dose decreased by 8% over study time, but no significant effect was seen on BMD. BMD did not change significantly after switching from immediate- to modified-release HC.ConclusionsThe use of prednisolone as hormone replacement therapy results in significantly lower BMD compared to HC. Patients on low-dose HC replacement therapy showed unchanged Z-scores within the normal reference range during the study period.

Is There an Association Between Cortisol and Hypertension in Overweight or Obese Children?

Objective:The precise mechanisms behind the development of hypertension in overweight or obese children are not yet completely understood. Alterations in hypothalamic-pituitary-adrenal axis activity may play a role. We aimed to investigate the association between cortisol parameters and hypertension in overweight or obese children.Methods:Random urine (n=180) and early-morning saliva samples (n=126) for assessment of cortisol and cortisone were collected from 1) hypertensive overweight children (n=50), 2) normotensive overweight children (n=145), and 3) normotensive non-overweight children (n=75).Results:The age of participants was 10.4±3.3 years and 53% were boys. The urinary cortisol-to-cortisone ratio [β 1.11, 95% confidence interval (CI) 1.05-1.19] as well as urinary cortisol/creatinine (β 1.38, 95% CI 1.09-1.54), and cortisone/creatinine ratios (β 1.26, 95% CI 1.17-1.36) were significantly higher in overweight or obese than in non-overweight children. After adjusting for body mass index-standard deviation score and urinary cortisone/creatinine ratio, but not cortisol/creatinine ratio, was significantly associated with presence of hypertension (β 1.12, 95% CI 1.02-1.23). Salivary cortisol and cortisone levels were significantly lower in overweight or obese than in non-overweight children (β -4.67, 95% CI -8.19- -1.15, and β 0.89, 95% CI 0.80-0.97 respectively). There were no significant differences in cortisol parameters between hypertensive and normotensive overweight or obese children.Conclusion:This study provided further evidence for an increased cortisol production rate with decreased renal 11β-hydroxysteroid dehydrogenase 2 activity and flattening of early-morning peak cortisol and cortisone in overweight or obese children. However, there were no significant differences in cortisol parameters between hypertensive and normotensive overweight and obese children.

The adrenocortical function studies in children.

The recent advances in the laboratory procedures make it possible to study endocrinological states in children more easily and more accurately even in the neonatal period. The successes in purification and the determination of chemical structures of various hormones and their releasing factors make it possible to carry out various loading tests. The progress in the measurement of various hormones and their metabolites especially in the field of radioimmunoassay is really remarkable.If we took adrenocortical function studies as an example, urinary 17 hydroxycorticosteroid was the only reliable item about ten years ago, then plasma 17-OHCS determination using Porter-Silver chromogen was introduced followed by plasma 11-OHCS determination with fluorescence spectrophotometry. Then, cortisol production rate determination became possible using radio-isotope dilution technique, and at present, plasma cortisol can be measured directly with protein competitive radio-immunoassay. Thus, the adrenocortical function studies in the pediatric age group has become easier and more reliable. The author likes to present some endocrinological results in children using various methods and now they can be applied in the clinical work.

MECHANISMS IN ENDOCRINOLOGY: New concepts to further unravel adrenal insufficiency during critical illness

The concept of 'relative' adrenal insufficiency during critical illness remains a highly debated disease entity. Several studies have addressed how to diagnose or treat this condition but have often yielded conflicting results, which further fuelled the controversy. The main reason for the controversy is the fact that the pathophysiology is not completely understood. Recently, new insights in the pathophysiology of the hypothalamic-pituitary-adrenal axis response to critical illness were generated. It was revealed that high circulating levels of cortisol during critical illness are explained more by reduced cortisol breakdown than by elevated cortisol production. Cortisol production rate during critical illness is less than doubled during the day but lower than in healthy subjects during the night. High plasma cortisol concentrations due to reduced breakdown in turn reduce plasma ACTH concentrations via feedback inhibition, which with time may lead to an understimulation and hereby a dysfunction of the adrenal cortex. This could explain the high incidence of adrenal insufficiency in the prolonged phase of critical illness. These novel insights have created a new framework for the diagnosis and treatment of adrenal failure during critical illness that has redirected future research.

Reduction in daily hydrocortisone dose in adrenal insufficiency improves significantly bone mineral density – Results from a 2-years prospective trial

Introduction: Patients with primary adrenal insufficiency (PAI) and patients with congenital adrenal hyperplasia (CAH) receive life-long glucocorticoid (GC) replacement therapy. Today daily GC doses are still higher than the reported adrenal cortisol production rate, and are not able to reproduce the physiological secretion pattern. This might result in long-term morbidities such as osteoporosis. Until now no prospective trial was performed investigating the long-term effect of GC dose changes in PAI and CAH patients.

Urine free cortisol in the diagnosis of Cushing's syndrome: is it worth doing and, if so, how?

Urine free cortisol in the diagnosis of Cushing's syndrome: is it worth doing and, if so, how?

Short-term, low-dose GH therapy improves insulin sensitivity without modifying cortisol metabolism and ectopic fat accumulation in adults with GH deficiency.

Low-dose GH (LGH) therapy has been reported to improve insulin sensitivity in GH-deficient adults; however, the mechanism is unclear. Effects of LGH therapy on insulin sensitivity are mediated through changes in cortisol metabolism and ectopic fat accumulation. This was a double-blind, placebo-controlled, parallel, 3-month study. Seventeen GH-deficient adults were randomized to receive either daily LGH or placebo injections. Fasting blood samples were collected at baseline, and months 1 and 3, whereas hyperinsulinemic-euglycemic clamps, magnetic resonance spectroscopy scans, 24-hour cortisol production rates (CPRs), and sc abdominal fat biopsies were performed at baseline and month 3. Clamp glucose infusion rate, intramyocellular, extramyocellular, and intrahepatic lipid content, 24-hour CPRs, adipocyte size, and adipocyte 11β-hydroxysteroid dehydrogenase activity in adults with GH deficiency were evaluated. At month 1, LGH did not alter fasting levels of glucose, insulin, C-peptide, free fatty acid, adiponectin, total IGF-1, IGF-1 bioactivity, IGF-2, IGF binding protein (IGFBP)-2, or IGF-1 to IGFBP-3 molar ratio. At month 3, LGH increased clamp glucose infusion rates (P < .01) and IGF-1 to IGFBP-3 molar ratio (P < .05), but fasting glucose, insulin, C-peptide, free fatty acid, adiponectin, IGF-1 bioactivity, IGF-2, IGFBP-2, 24-hour CPRs, adipocyte size, adipocyte 11β-hydroxysteroid dehydrogenase activity, intrahepatic lipid, extramyocellular, or intramyocellular were unchanged. In the placebo group, all within-group parameters from months 1 and 3 compared with baseline were unchanged. Short-term LGH therapy improves insulin sensitivity without inducing basal lipolysis and had no effect on cortisol metabolism and ectopic fat accumulation in GH-deficient adults. This may reflect an LGH-induced increase in IGF-1 to IGFBP-3 molar ratio exerting insulin-like effects through the abundant muscle IGF-1 receptors, but this hypothesis requires confirmation with further studies.

Cortisol metabolism in critical illness: implications for clinical care.

Critical illness is uniformly characterized by elevated plasma cortisol concentrations, traditionally attributed exclusively to increased cortisol production driven by an activated hypothalamic pituitary adrenal axis. However, as plasma adrenocorticotropic hormone (ACTH) concentrations are often not elevated or even low during critical illness, alternative mechanisms must contribute. Recent investigations revealed that plasma clearance of cortisol is markedly reduced during critical illness, explained by suppressed expression and activity of the main cortisol metabolizing enzymes in liver and kidney. Furthermore, unlike previously inferred, cortisol production rate in critically ill patients was only moderately increased to less than double that of matched healthy subjects. In the face of low-plasma ACTH concentrations, these data suggest that other factors drive hypercortisolism during critical illness, which may suppress ACTH by feedback inhibition. These new insights add to the limitations of the current diagnostic tools to identify patients at risk of failing adrenal function during critical illness. They also urge to investigate the impact of lower hydrocortisone doses than those hitherto used. Recent novel insights reshape the current understanding of the hormonal stress response to critical illness and further underline the need for more studies to unravel the pathophysiology of adrenal (dys)functioning during critical illness.

Reduction in Cortisol Inactivation is Part of the Adrenal Stress Response to Cardiac and Noncardiac Pediatric Surgery: A Prospective Study Using Gas Chromatography-Mass Spectrometry Analysis

We examined the hypothesis that major cardiac surgery triggers a more intense adrenal stress response than less intensive noncardiac surgery, which then alters cortisol inactivation. Urinary excretion rates of glucocorticoid metabolites were determined before and after surgery using gas chromatography-mass spectrometry in 29 children undergoing scheduled major cardiac surgery and 17 control children undergoing conventional noncardiac surgery in a prospective observational study. Excretion rates of glucocorticoid metabolites were summed and corrected for creatinine excretion to calculate cortisol production rates (mg/mmol creatinine/m(2) body surface area). Precursor/product ratios from individual metabolites were calculated to characterize cortisol inactivation (11β-hydroxysteroid dehydrogenase). Postoperatively, median cortisol production rates increased in both groups ( from 2.7 to 9.3; controls: from 2.7 to 5.8; p<0.001) with no significant difference between groups (p=0.12). Ratios of cortisol to cortisone metabolites, indicating the overall activity of 11β-hydroxysteroid dehydrogenase, increased postoperatively in both groups (p<0.001). In conclusion, surgery resulted in a distinct postoperative increase in cortisol production. In contrast to our hypothesis, children undergoing major cardiac surgery did not show an increased adrenal stress response compared to children undergoing conventional surgery. Furthermore, the reduction in cortisol inactivation appears to be an essential part of the stress response to pediatric surgery in general.

Relation of inflammation and liver function with the plasma cortisol response to adrenocorticotropin in early lactating dairy cows

In this study we examined the relationship between cortisol and inflammatory status in early lactating dairy cows after a stimulation test of the adrenal cortex. Twenty-four cows were grouped into quartiles (6 cows per each quartile) in accordance with the liver activity index (based on plasma concentration of negative acute phase proteins in early lactation); the quartiles were lower (LO; cows with the lowest liver functionality), intermediate lower, intermediate upper, and upper (UP; cows with the highest liver functionality). Each cow was injected i.v. with 20µg of a synthetic analog of ACTH at 35d in milk (DIM). Blood samples were taken to assess inflammatory status, and at 0, 30, and 60min after ACTH challenge to measure total cortisol. The free cortisol fraction was analyzed in the LO and UP quartiles and the bound cortisol fraction was estimated as the difference between total and free cortisol. The LO, in comparison with the other quartiles, suffered a more severe inflammatory status, with the highest values of haptoglobin, reactive oxygen metabolites, and total nitric oxide metabolites and the lowest concentration of direct or indirect markers of negative acute phase proteins. The cows in the LO quartile had the highest values of plasma nonesterified fatty acids and β-hydroxybutyrate at 7 DIM, suggesting a more severe body lipid mobilization. The LO quartile cows showed the highest frequency of health problems and the lowest milk yield in the first 35 DIM. Thirty minutes after the ACTH treatment, the concentration of total cortisol was lower in LO in comparison to other groups. Similarly, the bound cortisol fraction was lower in LO versus UP. The adrenal response appeared inversely related with health status after calving (e.g., lower in LO cows, experiencing the most severe inflammatory status). The lower increase in cortisol after the ACTH challenge in cows with greater inflammation (LO quartile) seems a consequence of the lower availability of cortisol-binding globulin synthetized by the liver, but other mechanisms can be involved (e.g., rate of cortisol production, secretion, and metabolic clearance). Our data provide evidence that inflammation and metabolic changes reduce the concentration of circulating plasma cortisol during an acute stress. Hence, the acute phase response in dairy cows should be taken into account to interpret the results obtained from stimulation tests of the adrenal cortex.

The role and regulation of 11β-hydroxysteroid dehydrogenase type 1 in obesity and the metabolic syndrome.

The cortisol regenerating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) amplifies tissue glucocorticoid levels, particularly in the liver and adipose tissue. The importance of this enzyme in causing metabolic disease was highlighted by transgenic mice which over- or under-expressed 11β-HSD1; consequently, selective 11β-HSD1 inhibitors have been widely developed as novel agents to treat obesity and type 2 diabetes mellitus (T2DM). This review focuses on the importance of 11β-HSD1 in humans which has been more difficult to ascertain. The recent development of a deuterated cortisol tracer has allowed us to quantify in vivo cortisol production by 11β-HSD1. These results have been surprising, as cortisol production rates by 11β-HSD1 are at least equivalent to that of the adrenal glands. The vast majority of this production is by the liver (>90%) with a smaller contribution from subcutaneous adipose tissue and possibly skeletal muscle, but with no detectable production from visceral adipose tissue. This tracer has also allowed us to quantify the tissue-specific regulation of 11β-HSD1 observed in obesity and obesity-associated T2DM, determine the likely basis for this dysregulation, and identify obese patients with T2DM as the group most likely to benefit from selective inhibition of 11β-HSD1. Some of these inhibitors have now reached Phase II clinical development, demonstrating efficacy in the treatment of T2DM. We review these results and discuss whether selective 11β-HSD1 inhibitors are likely to be an important new therapy for metabolic disease.

What is the best approach to tailoring hydrocortisone dose to meet patient needs in 2012?

Cortisol is an essential stress hormone and replacement with oral hydrocortisone is lifesaving in patients with adrenal insufficiency. Cortisol has a diurnal rhythm regulated by the central body clock and this rhythm is a metabolic signal for peripheral tissue clocks. Loss of cortisol rhythmicity is associated with fatigue, depression and insulin resistance. A general principle in endocrinology is to replace hormones to replicate physiological concentrations; however, the pharmacokinetics of oral immediate-release hydrocortisone make it impossible to fully mimic the cortisol rhythm and patients still have an increased morbidity and mortality despite replacement. Traditionally, physicians have replaced hydrocortisone with a total daily dose based on the diurnal 24-h cortisol production rate with hydrocortisone given twice or thrice daily, with the highest dose first thing in the morning. Monitoring treatment and dose titration has been much debated with some clinicians using cortisol day curves and others relying on clinical symptoms. The main challenge is that there is no established biomarker of cortisol activity. In addressing the clinical question, we have taken the view that an understanding of the cortisol circadian rhythm and hydrocortisone pharmacokinetics is essential when tailoring hydrocortisone dose. Using this approach, we have developed a thrice daily, weight-related, dosing regimen and a pharmacokinetic and clinical method to monitor treatment. Our argument for replicating the cortisol circadian rhythm is based on the observation that disruption of the rhythm is associated with ill health, and the few studies that have compared different treatment regimens. Further studies are required to definitively test the benefits of replacing the cortisol circadian rhythm in patients with adrenal insufficiency.