Clinical review: The pathogenetic role of cortisol in the metabolic syndrome: a hypothesis

The development of hypertension and hyperaldosteronism in a rodent model of life-long obesity

Aldosterone has been linked to the deleterious cardiovascular effects of obesity in humans. The association of aldosterone with obesity in rodents is less well defined, particularly in models of diet-induced obesity. We hypothesized that adrenal aldosterone production and aldosterone synthase expression would be increased in rats with obesity-induced hypertension. Male Sprague Dawley rats were fed a high-fat (HF: 36% fat) or control diet from 3 wk of age, and mean arterial pressure (MAP) was measured by telemetry. MAP was increased after 4 wk of HF diet; this was 6 wk before changes in body weight. Mineralocorticoid receptor antagonism did not prevent the HF-induced increase in MAP. After 17 wk on the diets, HF rats had increased body and fat weights (abdominal and epididymal) and were insulin resistant (Homeostasis Model Assessment index: 3.53 ± 0.43 vs. 8.52 ± 1.77; control vs. HF, P < 0.05). Plasma aldosterone levels were increased in the HF rats (64.14 ± 14.96 vs. 206.25 ± 47.55 pg/ml; control vs. HF, P < 0.05). This occurred independently of plasma renin activity (4.8 ± 0.92 vs. 4.73 ± 0.66 ng/ml/h, control vs. HF). The increase in aldosterone was accompanied by a 2-fold increase in adrenal aldosterone synthase mRNA expression and zona glomerulosa hypertrophy. Rats were also studied after 8 wk of HF diet, a time when MAP, but not body weight, was increased. At this time plasma aldosterone was unchanged but plasma renin activity was increased (4.4 ± 0.5 vs. 8.1 ± 1.3 ng/ml/h; control vs. HF, P < 0.05). These studies suggest that rats fed a HF diet from weaning may be a useful model for studying obesity-associated hyperaldosteronism.

Does insulin resistance co-exist with glucocorticoid resistance in the metabolic syndrome? Studies comparing skin sensitivity to glucocorticoids in individuals with and without acanthosis nigricans

Background

The metabolic syndrome is associated with increased risk for both diabetes and coronary artery disease, which insulin resistance alone does not satisfactorily explain. We propose an additional and complementary underlying mechanism of glucocorticoid resistance.

Results

Using acanthosis nigricans (AN) and skin vasoconstrictor (SVC) response to topically applied beclomethasone dipropionate as markers of insulin and glucocorticoid resistance, respectively, we compared anthropometric, biochemical, pro-inflammatory markers and the SVC response in subjects with AN in two studies: STUDY 1 was used to compare subjects with AN (Grade 4, n = 32), with those without AN (n = 68) while STUDY 2 compared these responses among a cross-section of diabetic patients (n = 109) with varying grades of AN (grade 0, n = 30; grade 1, n = 24; grade 2, n = 18; grade 3, n = 25; grade 4, n = 12).

Findings

In both studies there was an inverse relationship between AN Grade 4 and the SVC response, (P < 0.001). In STUDY 1, AN Grade 4 was associated with age, waist circumference, BMI, fasting blood glucose, plasma lipids and hs-CRP (P < 0.05). SVC was an independent predictor of CRP and those with combined AN and a negative SVC response, CRP levels were highest. In Study 2 when the SVC response in subjects with type 2 diabetes mellitus with varying degrees of AN was studied, it showed that for any degree of AN, the SVC response is more likely to be negative and was independent of gender and ethnicity.

Conclusion

An absent SVC response represents a new biomarker for the metabolic syndrome and the exaggerated inflammatory response, which characterizes the metabolic syndrome, may be an outcome of deficient glucocorticoid action in vascular tissue.

Timing and duration of sleep and meals in obese and normal weight women. Association with increase blood pressure

The aim was to evaluate the efficiency and duration of sleep and meals in normal-weight and obese women and the impact of these factors on metabolic syndrome (MetS) variables. The study was conducted in 70 women, normal-weight women (n=20) and obese women (n=50). Anthropometric variables, plasma glucose, lipids and ghrelin concentrations were determined. Blood pressure measurement was performed before lunch and before dinner for a week on alternate days. Subjects were instructed to keep a sleep and feeding diary. In general, obese women displayed longer and a significantly higher number of awakenings per week than normal-weight women and a higher duration of naps. Sleep efficiency was significantly lower in obese women. The higher intake in energy in the obese women was due to snacking differences. Moreover, higher sleep efficiency was correlated with a decrease in the diastolic blood pressure evening/morning ratio. Interestingly, among normal-weight women, visceral fat increased with the number of awakenings while plasma ghrelin was inversely correlated with meal duration (P=0.027). In conclusion, obese women had lower sleep efficiency, ate more quickly and spent more time eating and sleeping during the daytime hours than normal-weight women. Of note, sleep efficiency was associated with MetS features. Further interventions in obesity could include educating patients in food timing and in healthier sleep-hygiene practices, helping them to modify bad sleep habits.

Overexpression of 11β-hydroxysteroid dehydrogenase type 1 in visceral adipose tissue and portal hypercortisolism in non-alcoholic fatty liver disease

BACKGROUND

The enzyme 11β-hydroxysteroid-dehydrogenase type 1 (11β-HSD1) catalyses the reactivation of intracellular cortisol. We explored the potential role of 11β-HSD1 overexpression in visceral adipose tissue (VAT) in non-alcoholic fatty liver disease (NAFLD) assessing sequential changes of enzyme expression, in hepatic and adipose tissue, and the occurrence of portal hypercortisolism in obese mice. 11β-HSD1 expression was also assessed in tissues from obese patients undergoing bariatric surgery.

METHODS

Peripheral and portal corticosterone levels and liver histology were assessed in ob/ob mice at two time points (8-12 weeks of age). 11β-HSD1 tissue expression was assessed in by RT-pcr in ob/ob mice and in 49 morbidly obese patients.

RESULTS

Portal corticosterone serum levels were higher in obese mice with a 26% decrease between 8 and 12 weeks of age (controls: 78.3 ± 19.7 ng/ml, 8-week-old ob/ob: 167.5 ± 14.5 ng/ml and 12-week-old ob/ob: 124.3 ± 28 ng/ml, P < 0.05). No significant differences were found in peripheral corticosterone serum levels. Expression of 11β-HSD1 was lower in the liver [-45% at 8 weeks and -35% at 12-weeks (P = 0.0001)] and highly overexpressed in VAT in obese mice, compared to controls (128-fold higher in 8-week-old ob/ob and 41-fold higher in 12-week-old ob/ob, P < 0.01). No significant differences were seen in the expression of 11β-HSD1 in subcutaneous adipose tissue. In multivariate analysis, human 11β-HSD1 expression in VAT (OR: 1.385 ± 1.010-1.910) was associated with NAFLD.

CONCLUSION

Murine NAFLD is associated with portal hypercortisolism and11β-HSD1 overexpression in VAT. In humans, 11β-HSD1 VAT expression was associated with the presence of NAFLD. Thus, local corticosteroid production in VAT may contribute to NAFLD pathogenesis.

Salivary cortisol levels are associated with outcomes of weight reduction therapy in obese Japanese patients

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis can increase the risk of cardiovascular disease (CVD). However, the detailed relationships of HPA axis activity with weight reduction and CVD risk factors in obese patients have not been examined. This study was designed to elucidate the associations of salivary cortisol levels with weight reduction and CVD risk factors in obese patients. As a marker of HPA axis activity, we measured the morning salivary cortisol levels of 83 obese Japanese outpatients. We also examined metabolic parameters, inflammatory markers, and indicators of arterial stiffness, that is, the pulse wave velocity and cardio-ankle vascular index. All 83 obese patients underwent 3-month weight reduction therapy with lifestyle modification. At the baseline, multivariate regression analysis revealed that only logarithmic transformation of C-reactive protein (β = 0.258, P < .05) and cardio-ankle vascular index (β = 0.233, P < .05) were independent determinants of the salivary cortisol levels. However, other metabolic parameters were not significantly associated with the salivary cortisol levels. In addition, lower salivary cortisol levels and higher body weight at the baseline were the only independent determinants of successful weight loss through the weight reduction therapy (P < .01). The present study demonstrates that the baseline morning salivary cortisol levels are significantly associated with the levels of an inflammatory marker, arterial stiffness, and successful weight reduction in obese patients. Therefore, salivary cortisol could be a useful marker for assessing and managing body weight and CVD risk factors in obese patients.

Marrow fat metabolism is linked to the systemic energy metabolism

Recent advances in understanding the role of bone in the systemic regulation of energy metabolism indicate that bone marrow cells, adipocytes and osteoblasts, are involved in this process. Marrow adipocytes store significant quantities of fat and produce adipokines, leptin and adiponectin, which are known for their role in the regulation of energy metabolism, whereas osteoblasts produce osteocalcin, a bone-specific hormone that has a potential to regulate insulin production in the pancreas and adiponectin production in fat tissue. Both osteoblasts and marrow adipocytes express insulin receptor and respond to insulin-sensitizing anti-diabetic TZDs in a manner, which tightly links bone with the energy metabolism system. Metabolic profile of marrow fat resembles that of both, white and brown fat, which is reflected by its plasticity in acquiring different functions including maintenance of bone micro-environment. Marrow fat responds to physiologic and pathologic changes in energy metabolism status by changing volume and metabolic activity. This review summarizes available information on the metabolic function of marrow fat and provides hypothesis that this fat depot may acquire multiple roles depending on the local and perhaps systemic demands. These functions may include a role in bone energy maintenance and endocrine activities to serve osteogenesis during bone remodeling and bone healing.

Stress and the HPA axis: role of glucocorticoids in alcohol dependence

Stress has long been suggested to be an important correlate of uncontrolled drinking and relapse. An important hormonal response system to stress-the hypothalamic-pituitary-adrenal (HPA) axis-may be involved in this process, particularly stress hormones known as glucocorticoids and primarily cortisol. The actions of this hormone system normally are tightly regulated to ensure that the body can respond quickly to stressful events and return to a normal state just as rapidly. The main determinants of HPA axis activity are genetic background, early-life environment, and current life stress. Alterations in HPA axis regulation are associated with problematic alcohol use and dependence; however, the nature of this dysregulation appears to vary with respect to stage of alcohol dependence. Much of this research has focused specifically on the role of cortisol in the risk for, development of, and relapse to chronic alcohol use. These studies found that cortisol can interact with the brain's reward system, which may contribute to alcohol's reinforcing effects. Cortisol also can influence a person's cognitive processes, promoting habit-based learning, which may contribute to habit formation and risk of relapse. Finally, cortisol levels during abstinence may be useful clinical indicators of relapse vulnerability in alcohol-dependent people.

Endocannabinoids and the cardiovascular response to stress

Stress activates the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS), resulting in cardiovascular responses. The endocannabinoid system (ECS), a ubiquitously expressed lipid signalling system, modulates both HPA and SNS activity. The purpose of this review is to explore the possible involvement/role of the ECS in the cardiovascular response to stress. The ECS has numerous cardiovascular effects including modulation of blood pressure, heart rate, the baroreflex, and direct vascular actions. It is also involved in a protective manner in response to stressors in cardiac preconditioning, and various stressors (for example, pain, orthostasis and social stress) increase plasma levels of endocannabinoids. Given the multitude of vascular effects of endocannabinoids, this is bound to have consequences. Beneficial effects of ECS upregulation could include cardioprotection, vasodilatation, CB(2)-mediated anti-inflammatory effects and activation of peroxisome proliferator-activated receptors. Negative effects of endocannabinoids could include mediation of the effects of glucocorticoids, CB(1)-mediated metabolic changes, and metabolism to vasoconstrictor products. It is also likely that there is a central role for the ECS in modulating cardiovascular activity via the HPA and SNS. However, much more work is required to fully integrate the role of the ECS in mediating many of the physiological responses to stress, including cardiovascular responses.

The expression of omental 11β-HSD1 is not increased in severely obese women with metabolic syndrome

OBJECTIVE

Plasma cortisol in obese subjects does not differ from that in normoweight subjects. Extra-adrenal cortisol production by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) can result in local hypercortisolemia. The aim of the present study was to examine the role of visceral hypercortisolemia in the development of metabolic syndrome in severe obesity.

METHODS

Eight lean women during hysterectomy (controls) and 19 severely obese women during bariatric surgery were studied, 8 without metabolic syndrome (OM- group) and 11 with it (OM+ group). Biopsies of omental and subcutaneous fat were performed in the severely obese women during surgery, but only omental biopsies in the controls. Expression of 11β-HSD1, glucocorticoid receptor α (GRα) and glucocorticoid receptor β (GRβ) was evaluated using real-time PCR.

RESULTS

Omental 11β-HSD1 expression was different between groups (one-way ANOVA, p < 0.01). Post-hoc analysis revealed that mean omental 11β-HSD1 mRNA levels were higher in the OM- group compared to controls, whereas they were similar when comparing the OM+ group with lean controls. Expression of 11β-HSD1 in subcutaneous fat was not different between OM+ and OM- groups. GRα expression in omental fat did not differ among groups or between omental and subcutaneous fat in severely obese patients. An expression of GRβ was not detected.

CONCLUSION

Contrary to our original hypothesis, omental 11β-HSD1 expression is not increased in the OM+ group.

Metabolic syndrome in the Mediterranean region: Current status

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities including abdominal obesity, impaired fasting glucose, hypertension and dyslipidemia. It seems to affect about one-fourth to one-fifth of the Mediterranean population, and its prevalence increases with age, being similar for both sexes and depending on the region and the definition used, with the National Cholesterol Education Program-Adult Treatment Panel-III (NCEP-ATPIII) definition being the most effective in the identification of glucose intolerance and cardiovascular risk. Except for these, MetS is associated with fatty liver disease, some forms of cancer, hypogonadism, and vascular dementia. The Mediterranean diet seems to be an ideal diet in patients with MetS, being rich in fibre, monounsaturated and polyunsaturated fats, and low in animal protein; and decreases the prevalence of MetS and cardiovascular disease risk. Except for weight loss, multifactorial intervention including insulin resistance reduction and normoglycemia, management of dyslipidemia, optimizing blood pressure and administration of low-dose aspirin for patients at high or moderately high cardiovascular disease (CVD) risk are additional targets. The present review provides current understanding about MetS in the Mediterranean region, focusing on its prevalence, clinical significance, and therapeutic strategy.

Effects of cord serum insulin, IGF-II, IGFBP-2, IL-6 and cortisol concentrations on human birth weight and length: pilot study

BACKGROUND

The IGF system is recognised to be important for fetal growth. We previously described increased Insulin-like growth factor binding protein (IGFBP)-2 cord serum concentrations in intra-uterine growth retardation (IUGR) compared with appropriate for gestational age (AGA) newborns, and a positive relationship of IGFBP-2 with Interleukin (IL)-6. The role of cortisol in the fetus at birth is largely unknown, and interactions among peptides are their real effect on birth size is unknown. Furthermore, almost all studies have previously assayed peptides in serum several years after birth, and follow-up data from pregnancy are always lacking. This study aimed at establishing and clarifying the effect of cord serum insulin, IGF-II, IGFBP-2, cortisol and IL-6 concentrations on birth length and weight.

METHODS

23 IUGR and 37 AGA subjects were followed up from the beginning of pregnancy, and were of comparable gestational age. Insulin, IGF-II, IGFBP-2, cortisol and IL-6 concentrations were assayed in cord serum at birth, and a multiple regression model was designed and applied to assess which were the significant biochemical determinants of birth size.

RESULTS

Insulin, cortisol, and IL-6, showed similar concentrations in IUGR and AGA as previously described, whereas IGF-II was lower, and IGFBP-2 increased in IUGR compared with AGA. IGF-II serum concentration was found to have a significant positive effect on both birth length (r:(:)0.546; p: 0.001) and weight (r:0.679; p: 0.0001). IGFBP-2 had a near significant negative effect on both birth weight (r:-0.342; p: 0.05) and length (r:-0.372; p:0.03).

CONCLUSION

IGF-II cord serum concentration was shown to have a significant positive effect on both birth length and weight, whereas IGFBP-2 had a significant negative effect. Insulin, cortisol, and IL-6 cord serum concentrations had no significant effect on birth size.

Increased urinary glucocorticoid metabolites are associated with metabolic syndrome, hypoadiponectinemia, insulin resistance and β cell dysfunction

Metabolic syndrome (MetS) may have increased cortisol (F) production caused by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in liver and adipose tissue and/or by HPA axis dysregulation. F is then mainly metabolized by liver reductases into inactive tetrahydrometabolites (THMs). We measured THM levels in patients with or without MetS and evaluate the correlation between THMs and anthropometric and biochemical parameters. We recruited 221 subjects, of whom 130 had MetS by ATP III. We evaluated F, cortisone (E), adipokines, glucose, insulin and lipid profiles as well as urinary (24h) F, E and THM levels. β Cell function was estimated by the HOMA Calculator. We observed that patients with MetS showed higher levels of THMs, HOMA-IR and leptin and lower levels of adiponectin and HOMA-β but no differences in F and E in plasma or urine. THM was associated with weight (r = +0.44, p<0.001), waist circumference (r = +0.38, p<0.01), glycemia (r = +0.37, p<0.01), and triglycerides (r = +0.18, p=0.06) and negatively correlated with adiponectin (r = -0.36, p<0.001), HOMA-β (r = -0.21, p<0.001) and HDL (r = -0.29, p<0.01). In a logistic regression model, THM levels were associated with hypertension, hyperglycemia and dyslipidemia. We conclude that MetS is associated with increased urinary THMs but not with F and E levels in plasma or urine. Increased levels of THM, reflecting the daily cortisol production subsequently metabolized, are correlated with hypoadiponectinemia, hypertension, dyslipidemia, insulin resistance and β cell dysfunction. A subtle increased in glucocorticoid production may further account for the phenotypic and biochemical similarities observed in central obesity and Cushing's syndrome.

A rodent model of rapid-onset diabetes induced by glucocorticoids and high-fat feeding

Glucocorticoids (GCs) are potent pharmacological agents used to treat a number of immune conditions. GCs are also naturally occurring steroid hormones (e.g. cortisol, corticosterone) produced in response to stressful conditions that are thought to increase the preference for calorie dense 'comfort' foods. If chronically elevated, GCs can contribute to the development of type 2 diabetes mellitus (T2DM), although the mechanisms for the diabetogenic effects are not entirely clear. The present study proposes a new rodent model to investigate the combined metabolic effects of elevated GCs and high-fat feeding on ectopic fat deposition and diabetes development. Male Sprague-Dawley rats (aged 7-8 weeks) received exogenous corticosterone or wax (placebo) pellets, implanted subcutaneously, and were fed either a standard chow diet (SD) or a 60% high-fat diet (HFD) for 16 days. Animals given corticosterone and a HFD (cort-HFD) had lower body weight and smaller relative glycolytic muscle mass, but increased relative epididymal mass, compared with controls (placebo-SD). Cort-HFD rats exhibited severe hepatic steatosis and increased muscle lipid deposition compared with placebo-SD animals. Moreover, cort-HFD animals were found to exhibit severe fasting hyperglycemia (60% increase), hyperinsulinemia (80% increase), insulin resistance (60% increase) and impaired β-cell response to oral glucose load (20% decrease) compared with placebo-SD animals. Thus, a metabolic syndrome or T2DM phenotype can be rapidly induced in young Sprague-Dawley rats by using exogenous GCs if a HFD is consumed. This finding might be valuable in examining the physiological and molecular mechanisms of GC-induced metabolic disease.

Social stratification and adolescent overweight in the United States: how income and educational resources matter across families and schools

The current study examines how poverty and education in both the family and school contexts influence adolescent weight. Prior research has produced an incomplete and often counterintuitive picture. We develop a framework to better understand how income and education operate alone and in conjunction with each other across families and schools. We test it by analyzing data from Wave 1 of the U.S.-based National Longitudinal Study of Adolescent Health (N = 16,133 in 132 schools) collected in 1994-1995. Using hierarchical logistic regression models and parallel indicators of family- and school-level poverty and educational resources, we find that at the family-level, parent's education, but not poverty status, is associated with adolescent overweight. At the school-level, the concentration of poverty within a school, but not the average level of parent's education, is associated with adolescent overweight. Further, increases in school poverty diminish the effectiveness of adolescents' own parents' education for protecting against the risks of overweight. The findings make a significant contribution by moving beyond the investigation of a single socioeconomic resource or social context. The findings push us to more fully consider when, where, and why money and education matter independently and jointly across health-related contexts.

Disassociation of liver and muscle insulin resistance from ectopic lipid accumulation in low-birth-weight individuals

CONTEXT

Low birth weight (LBW) is a marker of fetal stress and is associated with an increased prevalence of type 2 diabetes (T2D). Insulin resistance plays a prominent role in the development of T2D; however, the pathogenesis of T2D in LBW is controversial.

OBJECTIVE

The objective of the study was to assess whole-body and tissue-specific insulin sensitivity and intramyocellular lipid (IMCL) and hepatic lipid content in LBW and matched control subjects.

DESIGN

These were prospective and pair-matched studies.

SETTING

The study was conducted at Yale University Center for Clinical Investigation.

PARTICIPANTS

Young, lean, nonsmoking, sedentary LBW (n = 45) and matched control subjects participated in the study.

INTERVENTION

Interventions included an oral glucose tolerance test and hyperinsulinemic-euglycemic clamps and (1)H magnetic resonance spectroscopy.

MAIN OUTCOMES MEASURES

The main outcomes measures included insulin sensitivity index; whole-body and tissue-specific insulin sensitivity; liver lipid and IMCL contents; and fasting concentrations of cortisol, GH, and IGF-I as markers of the hypothalamic-pituitary-adrenal and IGFI/GH axes.

RESULTS

The LBW subjects were insulin resistant as reflected by a 20% reduction in insulin sensitivity index as compared with the controls (P = 0.0017), which could be attributed to both liver and muscle insulin resistance. There were no differences in IMCL or hepatic triglyceride content between LBW and control groups. In the LBW group, fasting plasma concentrations of cortisol (P = 0.01) and GH (P = 0.01) were increased, and IGF-I concentrations reduced (P < 0.05) a pattern, which may suggest potential dysregulation of the hypothalamic-pituitary-adrenal and IGF-I/GH axes.

CONCLUSION

These results support the hypothesis that fetal stress and LBW lead to liver and muscle insulin resistance and show that this is independent of lipid deposition in these organs.

Dexamethasone stimulates the expression of ghrelin and its receptor in rat hypothalamic 4B cells

Growth hormone (GH)-releasing peptides (GHRPs) are synthetic peptides that strongly induce GH release. GHRPs act via a specific receptor, the GHRP receptor (GHSR), of which ghrelin is a natural ligand. GHRPs also induce adrenocorticotropic hormone (ACTH) release in healthy subjects. GHRPs or ghrelin stimulate ACTH release via corticotropin-releasing factor (CRF) and arginin vasopressin in the hypothalamus. Stress-activated CRF neurons are suppressed by glucocorticoids in the hypothalamic paraventricular nucleus (PVN), while CRF gene is up-regulated by glucocorticoids in the PVN cells without the influence of input neurons. However, little is known about the regulation of ghrelin and GHSR type 1a (GHSR1a) genes by glucocorticoids in PVN cells. To elucidate the regulation of ghrelin and GHSR gene expression by glucocorticoids in PVN cells, here we used a homologous PVN neuronal cell line, hypothalamic 4B, because these cells show characteristics of the parvocellular neurons of the PVN. These cells also express ghrelin and GHSR1a mRNA. Dexamethasone increased ghrelin mRNA levels. A potent glucocorticoid receptor antagonist, RU-486, significantly blocked dexamethasone-induced increases in ghrelin mRNA levels. Dexamethasone also significantly stimulated GHSR1a mRNA and protein levels. Finally, ghrelin increased CRF mRNA levels, as did dexamethasone. Incubation with both dexamethasone and ghrelin had an additive effect on CRF and ghrelin mRNA levels. The ghrelin-GHSR1a system is activated by glucocorticoids in the hypothalamic cells.

Associations of salivary cortisol levels with metabolic syndrome and its components: the multi-ethnic study of atherosclerosis

CONTEXT

Prior research has identified associations between social-environmental factors and metabolic syndrome (MetS) components. The physiological mechanisms underlying these associations are not fully understood, but alterations in activity of the hypothalamic-pituitary-adrenal axis, a stress-responsive biological system, have been hypothesized to play a role.

OBJECTIVE

The aim of the study was to determine whether MetS diagnosis and specific clusters of MetS components (waist circumference, high-density lipoproteins, glucose, and blood pressure) are associated with cortisol levels.

DESIGN AND SETTING

We conducted cross-sectional analyses of data from the Multi-Ethnic Study of Atherosclerosis (MESA) study in the general community.

PATIENTS OR OTHER PARTICIPANTS

We studied a population-based sample of 726 adults (ages 48 to 89 yr) who do not have clinical diabetes.

INTERVENTION(S)

There were no interventions.

MAIN OUTCOME MEASURE(S)

Cortisol awakening response, cortisol decline across the waking day, and total cortisol output were analyzed (using 18 timed measures of salivary cortisol over 3 d).

RESULTS

Overall, we found little evidence that the presence of MetS or its components is related to cortisol output or patterns. Contrary to expectation, the presence of MetS was associated with lower rather than higher area under the curve, and no consistent pattern was observed when MetS components or subsets of components were examined in relation to cortisol.

CONCLUSIONS

Our findings do not support the hypothesis that differences in level or diurnal pattern of salivary cortisol output are associated with MetS among persons without clinical diabetes.

The adrenal peripheral clock: glucocorticoid and the circadian timing system

The mammalian circadian timing system is organized in a hierarchy, with the master clock residing in the suprachiasmatic nucleus (SCN) of the hypothalamus and subsidiary peripheral clocks in other brain regions as well as peripheral tissues. Since the local oscillators in most cells contain a similar molecular makeup to that in the central pacemaker, determining the role of the peripheral clocks in the regulation of rhythmic physiology and behavior is an important issue. Glucocorticoids (GCs) are a class of multi-functional adrenal steroid hormones, which exhibit a robust circadian rhythm, with a peak linked with the onset of the daily activity phase. It has long been believed that the production and secretion of GC is primarily governed through the hypothalamus-pituitary-adrenal (HPA) neuroendocrine axis in mammals. Growing evidence, however, strongly supports the notion that the periodicity of GC involves the integrated activity of multiple regulatory mechanisms related to circadian timing system along with the classical HPA neuroendocrine regulation. The adrenal-intrinsic oscillator as well as the central pacemaker plays a pivotal role in its rhythmicity. GC influences numerous biological processes, such as metabolic, cardiovascular, immune and even higher brain functions, and also acts as a resetting signal for the ubiquitous peripheral clocks, suggesting its importance in harmonizing circadian physiology and behavior. In this review, we will therefore focus on the recent advances in our understanding of the circadian regulation of adrenal GC and its functional relevance.

Ligand-independent phosphorylation of the glucocorticoid receptor integrates cellular stress pathways with nuclear receptor signaling

Glucocorticoids are stress hormones that maintain homeostasis through gene regulation mediated by nuclear receptors. We have discovered that other cellular stressors are integrated with glucocorticoid signaling through a new hormone-independent phosphorylation site, Ser134, on the human glucocorticoid receptor (GR). Ser134 phosphorylation is induced by a variety of stress-activating stimuli in a p38 mitogen-activated protein kinase (MAPK)-dependent manner. Cells expressing a mutant glucocorticoid receptor incapable of phosphorylation at Ser134 (S134A-GR) had significantly altered hormone-dependent genome-wide transcriptional responses and associated hormone-mediated cellular functions. The phosphorylation of Ser134 significantly increased the association of the GR with the zeta isoform of the 14-3-3 class of signaling proteins (14-3-3zeta) on chromatin promoter regions, resulting in a blunted hormone-dependent transcriptional response of select genes. These data argue that the phosphorylation of Ser134 acts as a molecular sensor on the GR, monitoring the level of cellular stress to redirect glucocorticoid-regulated signaling through altered 14-3-3zeta cofactor binding and promoter recruitment. This posttranslational modification allows prior cellular stress signals to dictate the transcriptional response to glucocorticoids.

Cognitive and emotional alterations are related to hippocampal inflammation in a mouse model of metabolic syndrome

Converging clinical data suggest that peripheral inflammation is likely involved in the pathogenesis of the neuropsychiatric symptoms associated with metabolic syndrome (MetS). However, the question arises as to whether the increased prevalence of behavioral alterations in MetS is also associated with central inflammation, i.e. cytokine activation, in brain areas particularly involved in controlling behavior. To answer this question, we measured in a mouse model of MetS, namely the diabetic and obese db/db mice, and in their healthy db/+ littermates emotional behaviors and memory performances, as well as plasma levels and brain expression (hippocampus; hypothalamus) of inflammatory cytokines. Our results shows that db/db mice displayed increased anxiety-like behaviors in the open-field and the elevated plus-maze (i.e. reduced percent of time spent in anxiogenic areas of each device), but not depressive-like behaviors as assessed by immobility time in the forced swim and tail suspension tests. Moreover, db/db mice displayed impaired spatial recognition memory (hippocampus-dependent task), but unaltered object recognition memory (hippocampus-independent task). In agreement with the well-established role of the hippocampus in anxiety-like behavior and spatial memory, behavioral alterations of db/db mice were associated with increased inflammatory cytokines (interleukin-1β, tumor necrosis factor-α and interleukin-6) and reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus but not the hypothalamus. These results strongly point to interactions between cytokines and central processes involving the hippocampus as important contributing factor to the behavioral alterations of db/db mice. These findings may prove valuable for introducing novel approaches to treat neuropsychiatric complications associated with MetS.

Labisia pumila extract down-regulates hydroxysteroid (11-beta) dehydrogenase 1 expression and corticosterone levels in ovariectomized rats

We evaluated the effects of a standardized Labisia pumila var. alata (LPva) extract on body weight change, hydroxysteroid (11-beta) dehydrogenase 1 (HSD11B1) expressions and corticosterone (CORT) level in ovariectomized (OVX) rats. The decoction of LPva has been used for generations among Malay women in Malaysia to maintain a healthy reproductive system.Thirty-six Sprague-Dawley OVX rats were treated orally with LPva extract (10, 20 or 50 mg/kg/day) or estrogen replacement (ERT) for 30 days. Sham operated rats were used as controls. Compared to untreated OVX rats, LPva-treated rats showed less weight gain and had significantly down-regulated HSD11B1 mRNA in liver tissues. HSD11B1 mRNA in adipose tissues increased by 55% (p < 0.05) in OVX rats but normalized in rats treated with LPva. Similarly, there was significant down-regulation (p < 0.05) of protein levels of HSD11B1 in both liver and adipose tissue of LPva and ERT groups, and CORT levels were significantly reduced in both groups of rats. This is the first study ever conducted to evaluate the beneficial effects of LPva in relation to weight gain caused by estrogen insufficiency. Results implied that the bioactive components in LPva extract affect not only HSD11B1 expressions in both adipose and liver tissues but also decrease circulating CORT. The extract should be explored for its potential use as a natural remedy for weight management.

Differential effects of glucocorticoids on energy homeostasis in Syrian hamsters

Syrian hamsters, like many humans, increase food intake and body adiposity in response to stress. We hypothesized that glucocorticoids (cortisol and corticosterone) mediate these stress-induced effects on energy homeostasis. Because Syrian hamsters are dual secretors of cortisol and corticosterone, differential effects of each glucocorticoid on energy homeostasis were investigated. First, adrenal intact hamsters were injected with varying physiological concentrations of cortisol, corticosterone, or vehicle to emulate our previously published defeat regimens (i.e., 1 injection/day for 5 days). Neither food intake nor body weight was altered following glucocorticoid injections. Therefore, we investigated the effect of sustained glucocorticoid exposure on energy homeostasis. This was accomplished by implanting hamsters with supraphysiological steady-state pellets of cortisol, corticosterone, or cholesterol as a control. Cortisol, but not corticosterone, significantly decreased food intake, body mass, and lean and fat tissue compared with controls. Despite decreases in body mass and adiposity, cortisol significantly increased circulating free fatty acids, triglyceride, cholesterol, and hepatic triglyceride concentrations. Although corticosterone did not induce alterations in any of the aforementioned metabolic end points, Syrian hamsters were responsive to the effects of corticosterone since glucocorticoids both induced thymic involution and decreased adrenal mass. These findings indicate that cortisol is the more potent glucocorticoid in energy homeostasis in Syrian hamsters. However, the data suggest that cortisol alone does not mediate stress-induced increases in food intake or body mass in this species.

Selective Glucocorticoid Receptor (GR-II) Antagonist Reduces Body Weight Gain in Mice

Previous research has shown that mifepristone can prevent and reverse weight gain in animals and human subjects taking antipsychotic medications. This proof-of-concept study tested whether a more potent and selective glucocorticoid receptor antagonist could block dietary-induced weight gain and increase insulin sensitivity in mice. Ten-week-old, male, C57BL/6J mice were fed a diet containing 60% fat calories and water supplemented with 11% sucrose for 4 weeks. Groups (n = 8) received one of the following: CORT 108297 (80 mg/kg QD), CORT 108297 (40 mg/kg BID), mifepristone (30 mg/kg BID), rosiglitazone (10 mg/kg QD), or vehicle. Compared to mice receiving a high-fat, high-sugar diet plus vehicle, mice receiving a high-fat, high-sugar diet plus either mifepristone or CORT 108297 gained significantly less weight. At the end of the four week treatment period, mice receiving CORT 108297 40 mg/kg BID or CORT 108297 80 mg/kg QD also had significantly lower steady plasma glucose than mice receiving vehicle. However, steady state plasma glucose after treatment was not highly correlated with reduced weight gain, suggesting that the effect of the glucocorticoid receptor antagonist on insulin sensitivity may be independent of its mitigating effect on weight gain.

Ghrelin in obesity and endocrine diseases

Ghrelin shows orexigenic effect through its action on the hypothalamic appetite-regulating pathways, while in the periphery ghrelin increases adipose tissue accumulation and has a diabetogenic effect on the liver and pancreas. Adenosine monophosphate-activated protein kinase (AMPK) has been suggested as one of the mediators of ghrelin's effects. Plasma ghrelin levels are dependent on body mass index as well as food intake patterns. Ghrelin levels are in general reduced in obese individuals and in subjects with insulin resistance. In contrast to other forms of obesity, patients with Prader-Willi syndrome (PWS) display high levels of ghrelin, reduced visceral adiposity and relative hypoinsulinemia. Relationships between obesity and common genomic variants of GHRL and GHS-R genes have been studied. Ghrelin may have a role in the weight-reducing effect of bariatric surgery; however, this is a much debated issue. Altered ghrelin levels have also been observed in Cushing's syndrome and thyroid disease probably due to the secondary insulin resistance in these subjects.

Oral administration of γ-aminobutyric acid and γ-oryzanol prevents stress-induced hypoadiponectinemia

Metabolic syndrome is a cluster of risk factors including insulin resistance and type 2 diabetes and is found to associate partly with chronic stress at work in human. Adiponectin circulates in mammal blood mainly as a low molecular weight (LMW) trimer, hexamer, and a high molecular weight (HMW) multimers. Low circulating levels of adiponectin are related to metabolic syndrome. We have then investigated the influence of immobilization stress on plasma adiponectin concentrations in mice. Relative LMW and HMW adiponectin levels were markedly reduced by immobilization stress (0.66±0.07 and 0.59±0.06 after 102 h, respectively), significantly different from the control values (p<0.01 and 0.05, respectively). γ-Aminobutyric acid (GABA) and γ-oryzanol abundantly contained in germinated brown rice have some physiological functions. We further investigated the effect of GABA, γ-oryzanol, GABA plus γ-oryzanol on adiponectin levels in mice subjected to immobilization stress. GABA and γ-oryzanol significantly increased the relative LMW and HMW adiponectin levels under immobilization stress (1.10±0.11 and 0.99±0.19 after 102 h, respectively, for GABA; 1.08±0.17 and 1.15±0.17 after 102 h, respectively, for γ-oryzanol). Additionally, the co-administration of GABA and γ-oryzanol also increased both relative LMW and HMW adiponectin levels (1.02±0.07 and 0.99±0.10 after 102 h, respectively) and was effective in an earlier phase from 30 to 54 h. The results indicate that the co-administration of GABA and γ-oryzanol might be effective in preventing stress-induced hypoadiponectinemia in mice and be also a promising tool for improving metabolic syndrome aggravated by chronic stress.

Increased cortisol level: a possible link between climacteric symptoms and cardiovascular risk factors

OBJECTIVE

Vasomotor symptoms may increase the risk for cardiovascular diseases through still elusive mechanisms. Increased cortisol release may favor atherosclerosis. In this study, we tested whether vasomotor and psychological symptoms are associated with an increase in cortisol levels.

METHODS

A cross-sectional investigation on women in early menopause enrolled consecutively between January and June 2009 was conducted. This study was set at a menopause outpatient service at University Hospital. Participants included 85 healthy women who were 6 months to 5 years postmenopause. The 24-hour urinary cortisol level and Greene Climacteric Scale scores were evaluated. Anthropometric parameters and fasting blood samples for the determination of high-density lipoprotein (HDL) cholesterol, total cholesterol, triglycerides, glucose, and insulin levels were measured. Body mass index, waist-to-hip ratio, and homeostatic model assessment of insulin resistance were calculated. The relation between Greene Climacteric Scale scores and 24-hour urinary cortisol level and between 24-hour urinary cortisol level and lipid levels or insulin resistance was determined.

RESULTS

The Greene Climacteric Scale score for climacteric symptoms (coefficient of regression [CR], 1.343; 95% CI, 0.441-2.246) and body mass index (CR, 4.469; 95% CI, 1.259-7.678) explained 32.5% and 10.3%, respectively, of the variance in 24-hour urinary cortisol level (r = 0.428; P = 0.0003). Twenty-four-hour urinary cortisol level was inversely related to HDL-cholesterol level (CR, -0.065; 95% CI, -0.114 to -0.017; r = 0.283; P = 0.009) and was related to waist girth (CR, 0.685; 95% CI, 0.306-1.063) and homeostatic model assessment of insulin resistance (CR, 0.097; 95% CI, 0.032-0.162; r = 0.510; P = 0.0001).

CONCLUSIONS

In early postmenopausal women, the Greene Climacteric Scale score is associated with increased 24-hour urinary cortisol level. Increased cortisol level is associated with known risk factors for cardiovascular disease, such as insulin resistance and decreased HDL-cholesterol level.

Central nervous system lipocalin-type prostaglandin D2-synthase is correlated with orexigenic neuropeptides, visceral adiposity and markers of the hypothalamic-pituitary-adrenal axis in obese humans

Lipocalin-type prostaglandin D2-synthase (L-PGDS) is the main producer of prostaglandin D2 (PGD2) in the central nervous system (CNS). Animal data suggest effects of central nervous L-PGDS in the regulation of food intake and obesity. No human data are available. We hypothesised that a role for CNS L-PGDS in metabolic function in humans would be reflected by correlations with known orexigenic neuropeptides. Cerebrospinal fluid (CSF) and serum samples were retrieved from 26 subjects in a weight loss study, comprising a 3-week dietary lead-in followed by 12-weeks of leptin or placebo treatment. At baseline, CSF L-PGDS was positively correlated with neuropeptide Y (NPY) (ρ = 0.695, P < 0.001, n = 26) and galanin (ρ = 0.651, P < 0.001) as well as visceral adipose tissue (ρ = 0.415, P = 0.035). Furthermore, CSF L-PGDS was inversely correlated with CSF leptin (ρ = -0.529, P = 0.005) and tended to correlate inversely with s.c. adipose tissue (ρ = -0.346, P = 0.084). As reported earlier, leptin treatment had no effect on weight loss and did not affect CSF L-PGDS or NPY levels compared to placebo. After weight loss, the change of CSF L-PGDS was significantly correlated with the change of CSF NPY levels (ρ = 0.604, P = 0.004, n = 21). Because of the correlation between baseline CSF L-PGDS levels and visceral adipose tissue, we examined associations with hypothalamic-pituitary-adrenal (HPA) axis components. Baseline CSF L-PGDS was correlated with corticotrophin-releasing hormone (ρ = 0.764, P < 0.001) and β-endorphin (ρ = 0.491, P < 0.001). By contrast, serum L-PGDS was not correlated with any of the measured variables either at baseline or after treatment. In summary, CSF L-PGDS was correlated with orexigenic neuropeptides, visceral fat distribution and central HPA axis mediators. The importance of these findings is unclear but could suggest a role for CSF L-PGDS in the regulation of visceral obesity by interaction with the neuroendocrine circuits regulating appetite and fat distribution. Further interventional studies will be needed to characterise these interactions in more detail.

Functional variability in corticosteroid receptors is a major component of strain differences in fat deposition and metabolic consequences of enriched diets in rat

We aimed to distinguish mineralocorticoid (MR) from glucocorticoid receptor (GR) actions in the nutritional differences between the Fischer 344 (F344) and LOU/C (LOU) rat strains. The decrease of urinary Na+/K+ ratio induced via MR activation by aldosterone and decrease of circulating lymphocyte counts exerted via GR activation by dexamethasone revealed a higher efficiency of corticosteroid receptor in LOU than in F344 rats. Afterward, we submitted F344 and LOU male rats to adrenalectomy and to substitution treatments with agonists of MR or GR under 3 successive diets--standard, free choice between chow and pork lard, and an imposed high-fat/high-sugar diet--to explore the involvement of the interactions between activation of corticosteroid receptors and diet on food intake, body composition, and metabolic blood parameters in these rats. Lastly, we measured energy expenditure and substrate oxidization in various experimental conditions in LOU and F344 rats by indirect calorimetry. In LOU rats, we showed greater basal and MR-induced energy expenditure, diet-induced thermogenesis, and lipid oxidization. We showed that the F344 rat strain constitutes a relevant model of the unfavorable effects exerted by glucocorticoids via GR on food preference for high-calorie diets, abdominal fat deposition, diabetes, and other deleterious consequences of visceral obesity. Contrary to F344 rats, the LOU rats did not exhibit the expected visceral fat deposition linked to GR activation. This strain is therefore a relevant model of resistance to diet-induced obesity and to the deleterious effects exerted by glucocorticoids on metabolism.

Reliability of hypothalamic-pituitary-adrenal axis assessment methods for use in population-based studies

Population-based studies have been hampered in exploring hypothalamic-pituitary-adrenal axis (HPA) activity as a potential explanatory link between stress-related and metabolic disorders due to their lack of incorporation of reliable measures of chronic cortisol exposure. The purpose of this review is to summarize current literature on the reliability of HPA axis measures and to discuss the feasibility of performing them in population-based studies. We identified articles through PubMed using search terms related to cortisol, HPA axis, adrenal imaging, and reliability. The diurnal salivary cortisol curve (generated from multiple salivary samples from awakening to midnight) and 11 p.m. salivary cortisol had the highest between-visit reliabilities (r = 0.63-0.84 and 0.78, respectively). The cortisol awakening response and dexamethasone-suppressed cortisol had the next highest between-visit reliabilities (r = 0.33-0.67 and 0.42-0.66, respectively). Based on our own data, the inter-reader reliability (r(s)) of adrenal gland volume from non-contrast CT was 0.67-0.71 for the left and 0.47-0.70 for the right adrenal glands. While a single 8 a.m. salivary cortisol is one of the easiest measures to perform, it had the lowest between-visit reliability (R = 0.18-0.47). Based on the current literature, use of sampling multiple salivary cortisol measures across the diurnal curve (with awakening cortisol), dexamethasone-suppressed cortisol, and adrenal gland volume are measures of HPA axis tone with similar between-visit reliabilities which likely reflect chronic cortisol burden and are feasible to perform in population-based studies.

Stress in obesity: cause or consequence?

Obesity is a global public health challenge that increases the risk of various diseases including type 2 diabetes mellitus, hypertension and cancer, and will in the future cause further increases in the incidence of chronic disease. Understanding the mechanisms of obesity is critical if we are to prevent and treat this pandemic challenge. Diet and physical activity have traditionally been the major tasks in preventing and treating obesity. However, other mechanisms are now also being considered in the quest for knowledge and understanding of obesity, including the body's stress system and cortisol release. While it seems evident that stress is a cause of obesity, whether stress is also a consequence of obesity has up to now only briefly been discussed. The aim of this article is to elucidate how stress and obesity might be linked and discuss the cause/consequence relationship between the stress response and obesity. Our hypothesis is that stress and obesity interfere by positive feedback. This may be an important issue in both our understanding and coping of obesity.

Glucocorticoids, prenatal stress and the programming of disease

An adverse foetal environment is associated with increased risk of cardiovascular, metabolic, neuroendocrine and psychological disorders in adulthood. Exposure to stress and its glucocorticoid hormone mediators may underpin this association. In humans and in animal models, prenatal stress, excess exogenous glucocorticoids or inhibition of 11β-hydroxysteroid dehydrogenase type 2 (HSD2; the placental barrier to maternal glucocorticoids) reduces birth weight and causes hyperglycemia, hypertension, increased HPA axis reactivity, and increased anxiety-related behaviour. Molecular mechanisms that underlie the 'developmental programming' effects of excess glucocorticoids/prenatal stress include epigenetic changes in target gene promoters. In the case of the intracellular glucocorticoid receptor (GR), this alters tissue-specific GR expression levels, which has persistent and profound effects on glucocorticoid signalling in certain tissues (e.g. brain, liver, and adipose). Crucially, changes in gene expression persist long after the initial challenge, predisposing the individual to disease in later life. Intriguingly, the effects of a challenged pregnancy appear to be transmitted possibly to one or two subsequent generations, suggesting that these epigenetic effects persist.

WITHDRAWN: Ghrelin in obesity and endocrine diseases

The Publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.mce.2011.02.011. The duplicate article has therefore been withdrawn.

Disturbed glucoregulatory response to food intake after moderate sleep restriction

STUDY OBJECTIVES

Epidemiological studies point to a strong association between short sleep duration and the development of diabetes. We examined the hypothesis that short-term sleep loss decreases glucose tolerance and insulin sensitivity and, if so, how these changes relate to hypothalamic-pituitary-adrenal (HPA) secretory activity and markers of subclinical inflammation.

DESIGN

In a balanced, within-subject design, circulating glucose, insulin, C-peptide, glucagon, ACTH, cortisol, and IL-6 levels were closely monitored during a 15-h daytime period following 2 nights of restricted sleep (02:45-07:00) and 2 nights of regular sleep (bedtime 22:45-07:00), respectively.

SETTING

Time-deprivation suite within a university medical center sleep laboratory.

PARTICIPANTS

15 healthy, unmedicated normal-weight men.

INTERVENTION

Sleep restriction.

MEASUREMENTS AND RESULTS

Pre-breakfast concentrations of blood parameters were unchanged following sleep manipulation (P > 0.30). However, insulin and glucose peak responses to breakfast intake at 08:00 were distinctly increased by sleep restriction in comparison to regular sleep (398.5 ± 57.4 vs. 284.3 ± 51.5 pmol/L and 6.8 ± 0.3 vs. 6.1 ± 0.3 mmol/L, respectively; all P < 0.02), while glucagon responses were blunted by sleep loss (P = 0.03). There were no differences in circulating ACTH, cortisol, and IL-6 concentrations between the 2 conditions (all P > 0.25).

CONCLUSIONS

Data indicate an impairment of glucose tolerance after 2 days of sleep restriction to ~4 h that appears to be primarily caused by a reduction in insulin sensitivity. Unchanged HPA secretory activity and IL-6 concentrations argue against a mediation of these effects by stress-related or inflammatory mechanisms.

Endocrine diseases and the liver

Liver disease and endocrine disorders, both common in the general population, have a bidirectional and complex relationship. Certain liver diseases are more commonly associated with endocrine disorders, including nonalcoholic fatty liver disease, autoimmune hepatitis, and primary biliary cirrhosis. There may be an association between hepatitis C and type 2 diabetes mellitus as well as thyroid disorders, and sex hormonal preparations may cause specific hepatic lesions. The presence of relative adrenal insufficiency in patients with end-stage liver disease may have therapeutic implications in patients admitted with acute-on-chronic liver failure. The objective of this review is to focus on the effect of endocrine disorders on liver.

Corticotropin-releasing hormone (CRH) transgenic mice display hyperphagia with increased Agouti-related protein mRNA in the hypothalamic arcuate nucleus

Although glucocorticoid-induced hyperphagia is observed in the patients with glucocorticoid treatment or Cushing's syndrome, its molecular mechanism is not clear. We thus explored the expression of neuropeptide mRNAs in the hypothalamus related to appetite regulation in CRH over-expressing transgenic mice (CRH-Tg), a model of Cushing's syndrome. We measured food intake, body weight (including body fat weight) and plasma corticosterone levels in CRH-Tg and their wild-type littermates (WT) at 6 and 14 weeks old. We also examined neuropeptide Y (NPY), proopiomelanocortin (POMC) and Agouti-related protein (AgRP) mRNAs in the arcuate nucleus (ARC) using in situ hybridization. Circulating corticosterone levels in CRH-Tg were markedly elevated at both 6 and 14 weeks old. Body fat weight in CRH-Tg was significantly increased at 14 weeks old, which is considered as an effect of chronic glucocorticoid excess. At both 6 and 14 weeks old, CRH-Tg mice showed significant hyperphagia compared with WT (14w old: WT 3.9±0.1, CRH-Tg 5.1±0.7 g/day, p<0.05). Unexpectedly, NPY mRNA levels in CRH-Tg were significantly decreased at 14 weeks old (WT: 1571.5±111.2, CRH-Tg: 949.1±139.3 dpm/mg, p<0.05), and there were no differences in POMC mRNA levels between CRH-Tg and WT. On the other hand, AgRP mRNA levels in CRH-Tg were significantly increased compared with WT at both ages (14w old: WT 365.6±88.6, CRH-Tg 660.1±87.2 dpm/ mg, p<0.05). These results suggest that glucocorticoid-induced hyperphagia is associated with increased hypothalamic AgRP. Our results also indicate that hypothalamic NPY does not have an essential role in the increased food intake during glucocorticoid excess.

Morning cortisol is lower in obese individuals with normal glucose tolerance

BACKGROUND

There is no consensus on the role of cortisol in the pathogenesis of obesity and metabolic syndrome (MS). This cross-sectional study aimed to analyze the relationship of morning plasma cortisol and adrenocorticotropic hormone (ACTH) levels with body mass index (BMI) and glucose tolerance.

SUBJECTS AND METHODS

The sample frame was the "Offspring of individuals with diabetes study" database. A total of 358 offspring of individuals with type 2 diabetes mellitus (T2DM) and 287 individuals without a known family history of T2DM were recruited for the study. Subjects who were ≥10 years of age were selected from the database for analysis. Subjects with T2DM were excluded. All participants underwent a 75 g oral glucose tolerance test (OGTT), and blood samples were collected at 0, 30, 60, and 120 minutes for glucose, insulin and C-peptide. Plasma cortisol, ACTH, and lipid profile were estimated from the fasting sample.

RESULTS

Four hundred and ninety-five participants (305 males [62%] and 190 females [38%]) were included in the analysis. ACTH and cortisol levels were higher in normal-weight subjects than in overweight/obese subjects. Both ACTH and cortisol increased as fasting plasma glucose increased. Cortisol levels were significantly lower in offspring of T2DM subjects with MS than in offspring of T2DM subjects without MS. When adjusted for BMI, the significance was marginal. In males, cortisol levels were negatively correlated with early insulin secretion during OGTT (insulinogenic index [0-30]) and positively with waist circumference and serum high-density lipoprotein cholesterol. In females, fasting glucose and systolic blood pressure were significantly and positively correlated.

CONCLUSION

Body weight was correlated negatively with morning plasma cortisol and ACTH, whereas fasting glucose was correlated positively.