Adrenal Volume Research Articles

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.

Comparative Evaluation of Fetal Adrenal Gland Volume in Cases of Preterm Labor Versus Gestationally Matched Controls

Abstract Objectives: Efforts have been made to objectively estimate fetal adrenal gland activity by measuring maternal/fetal corticotropin releasing hormone (CRH) levels, CRH messenger RNA in human placenta and more recently the fetal adrenal gland volume estimation on ultrasonography. This study was planned to evaluate and compare the fetal adrenal gland volume in cases of preterm labor and gestationally matched controls. Study design: One hundred (100) pregnant women with singleton live pregnancy between 28 and 36 weeks of gestation were enrolled in the study to evaluate and compare the fetal adrenal gland volume in cases of preterm labor and gestationally matched controls. Materials and methods: The adrenal gland volume was assessed by three-dimensional ultrasonography, after which each woman was followed prospectively until delivery. Results: Primary outcome measures were spontaneous delivery within 5 days of ultrasonography, delivery before 37 completed weeks, and sonography–delivery interval. The se...

Ultrasound measurement of fetal adrenal gland enlargement: an accurate predictor of preterm birth

The objective of the study was to test whether ultrasound-measured fetal adrenal gland volume (AGV) and fetal zone enlargement (FZE) predicts preterm birth (PTB) better than cervical length (CL). Three-dimensional and 2-dimensional ultrasound were used prospectively to measure fetal AGV, FZE, and CL in women with preterm labor symptoms. We corrected AGV for fetal weight (cAGV). The ratio between whole gland depth (D) and central fetal zone depth (d) (d/D) was used to measure FZE. Ability of cAGV, d/D, and CL to predict PTB 7 days or less was compared. Twenty-seven of 74 women (36.5%) presenting between 21 and 34 weeks had PTB of 7 days or less. FZE greater than 49.5% was the single best predictor for PTB (sensitivity/specificity 100%/89%) compared with cAGV (81%/87%) and CL (56%/60%; P < .05). Prediction was independent of obstetrics history and tocolytic use. The 2-dimensional measurement of the adrenal gland FZE is highly effective performing superior to CL in identifying women at risk for PTB within 7 days.

Adrenal gland volume measurement in septic shock and control patients: a pilot study

To compare adrenal gland volume in septic shock patients and control patients by using semi-automated volumetry. Adrenal gland volume and its inter-observer variability were measured with tomodensitometry using semi-automated software in 104 septic shock patients and in 40 control patients. The volumes of control and septic shock patients were compared and the relationship between volume and outcome in intensive care was studied. The mean total volume of both adrenal glands was 7.2 ± 2.0cm(3) in control subjects and 13.3 ± 4.7cm(3) for total adrenal gland volume in septic shock patients (p < 0.0001). Measurement reproducibility was excellent with a concordance correlation coefficient value of 0.87. The increasing adrenal gland volume was associated with a higher rate of survival in intensive care. The present study reports that with semi-automated software, adrenal gland volume can be measured easily and reproducibly. Adrenal gland volume was found to be nearly double in sepsis compared with control patients. The absence of increased volume during sepsis would appear to be associated with a higher rate of mortality and may represent a prognosis factor which may help the clinician to guide their strategy.

Total Adrenal Volume But Not Testicular Adrenal Rest Tumor Volume Is Associated with Hormonal Control in Patients with 21-Hydroxylase Deficiency

Patients with 21-hydroxylase deficiency (21-OHD) have been shown to develop adrenal adenomas and, in males, testicular adrenal rest tumors (TARTs) at a high percentage. The aim of this study was to evaluate the interrelation of adrenal masses and TARTs as well as factors stimulating tumor growth of orthotopic and ectopic adrenal tissue in 21-OHD. In a cross-sectional study, 26 adult male patients with classic 21-OHD (15 salt wasting, 11 simple virilizing; age range, 18-48 yr) were clinically assessed according to their hormonal control. Magnetic resonance imaging of the adrenals (26 of 26) and of the testes (18 of 26) was performed. Adrenal size and morphology was compared to 26 age-matched controls. Combined adrenal volume of 21-OHD patients was significantly higher (median, 9.3 ml; range, 3.2-124.5 ml) in comparison to controls (median, 7.4 ml; range, 5.5-10.8 ml; P = 0.005). Morphologically, adrenals were classified as normal without nodules in 27% of 21-OHD patients compared to 69% of controls. None of the controls, but 42% of 21-OHD patients had an overall adrenal volume higher than 11 ml. Ten of 18 patients had TARTs with a median volume of 3.3 ml (range, 0.4-21.6 ml). Total adrenal volume and tumor size but not TART volume correlated positively with current parameters of hormonal control (androstenedione, morning 17-OHP in serum, pregnanetriol in 24-h urine; P < 0.001 for each). Baseline ACTH was independent of adrenal and TART volume. There was no correlation of total adrenal or adrenal tumor size with TART volume. These data provide indirect evidence that different factors regulate the growth of orthotopic adrenal tissue and ectopic adrenal remnants in TARTs.

A pilot study to assess the feasibility of measurement of adrenal gland volume by magnetic resonance imaging

Repeated computed tomography (CT) assessment of the adrenal glands is associated with a significant radiation burden. The increasing capabilities of magnetic resonance (MR) volumetric analysis of the adrenals make this a potentially alternative technique in man. To determine whether MR imaging could be used to measure adrenal volume, and to determine the intra- and interobserver variation and repeatability of MR volume imaging of adrenals in healthy human subjects. This was a single-cohort, sequential design, three-part study involving four MRI examinations per subject following ethical approval and informed consent. Information was collected on four healthy subjects (three male and one female). Two different investigators estimated the area of the adrenal gland for each of the 3-mm contiguous slices (and consequently adrenal volume). In order to estimate inter- and intrareader variability, a repeated-measures mixed model was fitted with adrenal volume as the dependent variable. In order to estimate any bias between readers, Bland-Altman methodology was applied. Intraobserver variation for adrenal gland volume is approximately 5% of a 3-cm(3 )adrenal gland. Interobserver variation is approximately 9% of a 3-cm(3) adrenal gland. Potential variation in measurement for adrenal volume from all sources equates to approximately 14% of a 3-cm(3) adrenal gland. Verification of image reading by a second investigator (consensus reading) reduces variability. Analysis of adrenal gland volume using MRI is a potentially reliable technique that could be used to assess a pathological change in adrenal size.

Longitudinal volume analysis from computed tomography: Reproducibility using adrenal glands as surrogate tumors

This study aims to determine the precision (reproducibility) of volume assessment in routine clinical computed tomography (CT) using adrenal glands as surrogate tumors. Seven patients at our institution were identified retrospectively as having received numerous abdominal CT scans (average 13.1, range 5 to 20). The adrenal glands were used as surrogate tumors, assuming no actual volume change. Left and right adrenal gland volumes were assessed by hand segmentation for each patient scan. Over 1240 regions of interest were outlined in total. The reproducibility, expressed as the coefficient of variation (COV), was used to characterize measurement precision. The average volumes were 5.9 and 4.5 cm3 for the left and right adrenal gland, respectively, with COVs of 17.8% and 18.9%, respectively. Using one patient’s data (20 scans) as an example surrogate for a spherical tumor, it was calculated that a 13% change in volume (4.2% change in diameter) could be determined with statistical significance at P=0.05. For this case, cursor positioning error in linear measurement of object size, by even 1 pixel on the CT image, corresponded to a significant change in volume (P=0.05). The precision of volume determination was dependent on total volume. Precision improved with increasing object size (r2 =0.367). Given the small dimensions of the adrenal glands, the ~18% COV is likely to be a high estimate compared to larger tumors. Modern CT scanners working with thinner sections (i.e. <1 mm) are likely to produce better measurement precision. The use of volume measurement to quantify changing tumor size is supported as a more precise metric than linear measurement.

Central effects of ghrelin on the adrenal cortex: a morphological and hormonal study

Ghrelin, a growth hormone secretagogue that exerts an important role in appetite and weight regulation, participates in the activation of the hypothalamo-pituitary-adrenal (HPA) axis. Male Wistar rats (5/group) received daily for 5 days, via an ICV (intracerebroventricular) cannula, 5 microl phosphate buffered saline with or without 1 microg of rat ghrelin. Two hours after the last injection, blood and adrenal glands were collected from decapitated rats for blood hormone analyses and histologic and morphometric processing. Ghrelin treatment resulted in increased (p<0.05) body weight (13%), absolute whole adrenal gland weight (18%) and whole adrenal gland volume (20%). The absolute volumes of the entire adrenal cortex, ZG, ZF, and ZR also increased (p<0.05) after ghrelin by 20%, 21%, 21% and 11%, respectively. Ghrelin-treated rats had elevated (p<0.05) blood concentrations of ACTH, aldosterone and corticosterone (68%, 32% and 67%, respectively). The data clearly provide both morphological and hormonal status that ghrelin acts centrally to exert a global stimulatory effect on the adrenal cortex. Clarifying of the ghrelin precise role in the multiple networks affecting the stress hormone release, besides its well known energy and metabolic unbalance effects, remains a very important research goal.

Quantitative Analysis of Adrenal Cortical Histological Alterations After Application of Medroxyprogesterone Acetate

Results. Gravimetric and variance analysis demonstrated the most remarkable decrease of the adrenal gland weight after the application of 75.0 mg/kg/bw MPA (from 35.66 ± 11.78 to 13.41 ± 8.41 mg (p<0.001). On the other hand, morphometric analysis demonstrated that adrenal cortex volume was the most significantly reduced from 11.30 ± 3.53 in the control group to 2.04 ± 0.90 mm3 in the group treated with 15.0 mg/kg bw MPA (p<0.0001). Adrenal cortex thickness was reduced from 846.06 ± 6.48 to 349.55 ± 4.84 μm after the application of 75.0 mg/kg bw (p < 0.001). After the application of the same dose the glomerular zone thickness was decreased from 48.02 ± 0.44 to 41.40 ± 0.43 μm (p < 0.001), the fascicular zone thickness from 480.72 ± 3.43 to 194.32 ± 2.80 μm (p <0.001) and the reticular zone thicknes reduced from 317.47 ± 4.80 to 113.85 ± 2.28 μm (p < 0.001). The volume of glomerular zone cell nuclei decreased most remarkably from 94.79 ± 0.96 μm3 after the application of 75.0 mg/kg bw to 60.12 ± 0.88 μm3 (p < 0.001). The volume of fascicular zone cell nuceli decreased from 166.30 ± 1.53 to 52.47 ± 0.89 μm3 (p < 0.001), while the volume of reticular zone cell nuceli reduced from 95.61 ± 1.03 to 47.68 ± 0.92 μm3 (p < 0.001). The analysis by means of χ2 test showed that the appearance of tissue necrotic changes in adrenal cortex had a statistical significance only after the application of the highest dose of MPA (p < 0.012).

Outcomes From 3144 Adrenalectomies in the United States

To assess the effect of surgeon volume and specialty on clinical and economic outcomes after adrenalectomy. Population-based retrospective cohort analysis. Healthcare Cost and Utilization Project Nationwide Inpatient Sample. Adults (>or=18 years) undergoing adrenalectomy in the United States (1999-2005). Patient demographic and clinical characteristics, surgeon specialty (general vs urologist), surgeon adrenalectomy volume, and hospital factors were assessed. The chi(2) test, analysis of variance, and multivariate linear and logistic regression were used to assess in-hospital complications, mean hospital length of stay (LOS), and total inpatient hospital costs. A total of 3144 adrenalectomies were included. Mean patient age was 53.7 years; 58.8% were women and 77.4% white. A higher proportion of general surgeons were high-volume surgeons compared with urologists (34.1% vs 18.2%, P < .001). Low-volume surgeons had more complications (18.2% vs 11.3%, P < .001) and their patients had longer LOS (5.5 vs 3.9 days, P < .001) than did high-volume surgeons; urologists had more complications (18.4% vs 15.2%, P = .03) and higher costs ($13,168 vs $11,732, P = .02) than did general surgeons. After adjustment for patient and provider characteristics in multivariate analyses, surgeon volume, but not specialty, was an independent predictor of complications (odds ratio = 1.5, P < .002) and LOS (1.0-day difference, P < .001). Hospital volume was associated only with LOS (0.8-day difference, P < .007). Surgeon volume, specialty, and hospital volume were not predictors of costs. To optimize outcomes, patients with adrenal disease should be referred to surgeons based on adrenal volume and laparoscopic expertise irrespective of specialty practice.

Changes of Body Composition in Bulimia Nervosa: Increased Visceral Fat and Adrenal Gland Size

To study the hypothesis that young women suffering from active bulimia nervosa (BN) have more visceral fat and increased adrenal gland volumes (AGV) than healthy controls (HC). Thirteen patients with BN of purging type and 11 healthy age and weight matched women (HC), aged between 19 and 36 years (mean 24 +/- 3 years), with a BMI of 19 to 29 (mean 24 +/- SD 3) were examined. BN was diagnosed by DSM-IV criteria and the severity of illness by the Eating Disorder Inventory (EDI-2). Whole body fat distribution and AGV were determined using a whole body magnetic resonance (MR) scan (T1w) and a 3D-sequence (T1w) at 1.5 Tesla. Salivary cortisol was determined at 9 AM and 4 PM. BN patients had significantly more visceral adipose tissue (VAT) (HC, 1589.3 +/- 967.6 ml versus 927.2 +/- 428.4 ml, p < .05) and an increased relative AGV (0.068% of body volume versus 0.048% of body volume, p < .05) compared with HC, although waist circumference and BMI did not differ. Although the VAT part in the upper abdomen was increased, especially the VAT of lower abdomen along with the pelvis or any subcutaneous fat compartment was not increased. The increase of the VAT volume and the increased AGV in BN women with purging point to chronic high stress levels associated with a hyperactivity of the hypothalamic-pituitary-adrenal axis in these patients. This is the first MR study showing morphological changes in stress associated endocrine organs of young BN patients.

Adrenal gland evaluation in septic shock patients: preliminary results of the first CT-scan study

Although critical-illness-related corticosteroid insufficiency (CIRCI) is common in septic shock patients, its diagnosis and management remain controversial [1,2]. The recent consensus conference on CIRCI reported that baseline total serum cortisol and that after 250 μg synthetic ACTH is insufficient to evaluate the adrenal response to sepsis [1]. To our knowledge, there is no CT-scan study that has evaluated adrenal gland imaging during septic shock. The aim of our study was to describe the adrenal gland volume evaluated by CT scan during septic shock.

Fetal stress. Focus on “Effects of acute acidemia on the fetal cardiovascular defense to acute hypoxemia” by Thakor and Giussani

what constitutes fetal stress, and what are the implications of fetal stress in the course of fetal development? Thakor and Giussani ([17][1]) address a fundamental component of the fetal stress response: acidemia and it role as a modulator of the hypothalamus-pituitary-adrenal (HPA) axis

Increase of Visceral Fat and Adrenal Gland Volume in Women with Depression: Preliminary Results of a Morphometric Mri Study

Depression is often accompanied by increased visceral adipose tissue (VAT), stress, enlarged adrenal glands, and an increased risk of cardiovascular disease. VAT turn-over is regulated by adrenal stress hormones such as cortisol. Aim of this study was to investigate the relationship between the adrenal volume as a marker for long-term stress and the volume fractions of several body fat compartments in healthy and depressive women. Ten depressive and 12 healthy women were investigated. Fat compartments (VAT, VAT in the upper abdomen, subcutaneous adipose tissue (SCAT), and adrenal volume) were measured by MRI. Depressive women revealed more VAT in the upper abdomen than the healthy. There was a significant correlation of age and Body Mass Index (BMI) with the visceral adipose tissue volume and adrenal gland size. In a partial correlation, Beck Depression Inventory (BDI) was correlated with VAT in the upper abdomen (r = 0.45, p < 0.05). The increase of adrenal volume and VAT and the correlation of BDI with VAT in the upper abdomen support the hypothesis of long-term production of stress hormones in depression. This study is a further step toward describing morphologic substrates of depression in endocrine organs.

COMPUTED TOMOGRAPHIC ADRENAL GLAND QUANTIFICATION IN CANINE ADRENOCORTICOTROPH HORMONE‐DEPENDENT HYPERADRENOCORTICISM

We conducted a retrospective study to determine whether multidetector computed tomography (CT) could be of value for adrenal gland assessment in dogs with pituitary-dependent hyperadrenocorticism. Adrenal gland attenuation and volume values of 49 dogs with hyperadrenocorticism were recorded and age, body weight, and gender were examined to determine if a relationship existed between these variables and adrenal gland morphology. There was not a statistically significant difference in mean X-ray attenuation of the left vs. right adrenal gland in normal dogs (35.3 +/- 6.1 HU), or in dogs with hyperadrenocorticism. The mean adrenal X-ray attenuation (+/- standard deviation [SD]) in dogs with microadenoma was 33.1 +/- 6.8 vs. 31.8 +/- 12.7 HU for dogs with macroadenoma, and these values were not statistically different. The mean volume of the left adrenal gland in normal dogs (0.59 +/- 0.17 cm3) was greater than that of the right adrenal gland (0.54 +/- 0.19 cm3) (P < 0.05). The mean CT volume (+/- SD) of the adrenal glands in dogs with microadenoma vs. macroadenoma were 1.60 +/- 1.25 vs. 2.88 +/- 1.60 cm3, respectively. There was no effect of age or gender on adrenal gland morphology or X-ray attenuation. The weight effect was the most important source of variation for the volume measurement in dogs with hyperadrenocorticism.

Fetal Adrenal Gland Volume and Cortisol/Dehydroepiandrosterone Sulfate Ratio in Inflammation-Associated Preterm Birth

Fetal adaptation to stress is regulated in part by the pituitary-adrenocortical system. The stress hormones dehydroepiandrosterone sulfate (DHEAS) and cortisol have opposing effects: cortisol suppresses while DHEAS enhances immune functions. We sought to estimate the impact of intraamniotic inflammation on fetal adrenal gland volume and cortisol-to-dehydroepiandrosterone sulfate ratio (fetal stress ratio) in pregnancies complicated by preterm birth. Fifty-one consecutive singleton fetuses of mothers who had an indicated amniocentesis to rule out infection were analyzed. Intraamniotic inflammation was assessed by proteomic profiling of amniotic fluid for the biomarkers of the Mass Restricted score. The Mass Restricted score ranges from 0 (biomarkers absent) to 4 (all biomarkers present), with Mass Restricted scores of 3 or 4 indicating severe intraamniotic inflammation. Fetal adrenal gland volume was assessed by three-dimensional ultrasonography and corrected for estimated fetal weight. Interleukin-6 (IL-6), cortisol, and DHEAS were measured by immunoassay. Women with intraamniotic inflammation delivered earlier (27.8+/-3.4 weeks, n=16, compared with 32.3+/-3.0 weeks, n=35, P<.001), and their fetuses had higher cord blood IL-6 (P=.011) and higher corrected adrenal gland volumes (P=.027). Cord blood IL-6 levels were in direct relationship with corrected adrenal volume (r=0.372, P=.019), fetal cortisol (r=0.428, P=.010), and DHEAS (r=0.521, P<.001). However, fetuses exposed to intraamniotic inflammation had an overall lower fetal stress ratio (P=.034). These results maintained after adjusting for gestational age, uterine contractions, and steroid exposure. Fetuses exposed to intraamniotic inflammation have higher adrenal gland volumes and lower cortisol-to-DHEAS ratios, suggesting that the fetal adrenocortical axis plays a role in the intrauterine adaptation to inflammation.

Limitations of Intraoperative Adrenal Remnant Volume Measurement in Patients Undergoing Subtotal Adrenalectomy

Recent studies have shown that a minimum of approximately one-third of one normal adrenal gland is required for sufficient adrenocortical stress capacity. Correlation between intraoperative measurement, determination of remnant size by computed tomography (CT), and adrenocortical stress capacity has not been examined so far. Twenty-two patients with familial pheochromocytoma (n=13), sporadic pheochromocytoma (n=3), and adrenocortical tumors (n=6) who underwent unilateral or bilateral subtotal adrenalectomy (STAE, 28 adrenal remnants) were prospectively studied. Patients were examined in a multi-slice CT to determine residual adrenal tissue and by ACTH test 4 days and 3 months postoperatively. There was a slight significant correlation between intraoperative and CT calculated volumes (r=0.77; p<0.001). However, volumes assessed by CT were almost doubled compared with intraoperative determination (p<0.001). Although recovery of adrenal function could be observed, no significant changes of remnant volumes could be detected within 3 months. In patients with familial pheochromocytoma, there was a significant correlation between residual adrenal volume and stimulated cortisol levels (P<0.001). A distinct minimum of adrenal volume for intact adrenocortical stress capacity could not be exactly determined; however, in one patient with only 10% residual adrenal tissue intact stress capacity was found. Residual adrenal tissue of approximately 10-15% offers intact stress capacity. However, an exact determination of the size of an adrenal remnant after STAE has limitations. CT gives larger volumes compared with intraoperative determination. For calculation of a volume-function correlation of residual adrenal tissue, in clinical practice, the determination of relative adrenal residual volume is acceptable.

Fetal Adrenal Gland Volume: A Novel Method to Identify Women at Risk for Impending Preterm Birth

Fetal Adrenal Gland Volume: A Novel Method to Identify Women at Risk for Impending Preterm Birth

Catecholamines and the Effects of Exercise, Training and Gender

Stress hormones, adrenaline (epinephrine) and noradrenaline (norepinephrine), are responsible for many adaptations both at rest and during exercise. Since their discovery, thousands of studies have focused on these two catecholamines and their importance in many adaptive processes to different stressors such as exercise, hypoglycaemia, hypoxia and heat exposure, and these studies are now well acknowledged. In fact, since adrenaline and noradrenaline are the main hormones whose concentrations increase markedly during exercise, many researchers have worked on the effect of exercise on these amines and reported 1.5 to >20 times basal concentrations depending on exercise characteristics (e.g. duration and intensity). Similarly, several studies have shown that adrenaline and noradrenaline are involved in cardiovascular and respiratory adjustments and in substrate mobilization and utilization. Thus, many studies have focused on physical training and gender effects on catecholamine response to exercise in an effort to verify if significant differences in catecholamine responses to exercise could be partly responsible for the different performances observed between trained and untrained subjects and/or men and women. In fact, previous studies conducted in men have used different types of exercise to compare trained and untrained subjects in response to exercise at the same absolute or relative intensity. Their results were conflicting for a while. As research progressed, parameters such as age, nutritional and emotional state have been found to influence catecholamine concentrations. As a result, most of the recent studies have taken into account all these parameters. Those studies also used very well trained subjects and/or more intense exercise, which is known to have a greater effect on catecholamine response so that differences between trained and untrained subjects are more likely to appear. Most findings then reported a higher adrenaline response to exercise in endurance-trained compared with untrained subjects in response to intense exercise at the same relative intensity as all-out exercise. This phenomenon is referred to as the 'sports adrenal medulla'. This higher capacity to secrete adrenaline was observed both in response to physical exercise and to other stimuli such as hypoglycaemia and hypoxia. For some authors, this phenomenon can partly explain the higher physical performance observed in trained compared with untrained subjects. More recently, these findings have also been reported in anaerobic-trained subjects in response to supramaximal exercise. In women, studies remain scarce; the results are more conflicting than in men and the physical training type (aerobic or anaerobic) effects on catecholamine response remain to be specified. Conversely, the works undertaken in animals are more unanimous and suggest that physical training can increase the capacity to secrete adrenaline via an increase of the adrenal gland volume and adrenaline content.

Gender Specific Correlations of Adrenal Gland Size and Body Fat Distribution: A Whole Body MRI Study

The aim of this study was to investigate the gender specific correlations of stress related tissues [adrenal gland volume (AV), visceral fat] and alimentary dependent fat compartments with cortisol concentrations in healthy male and female subjects. Fourteen men and 13 women were examined. Fat compartments [whole body fat, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SCAT)] were determined using whole body MRI. Adrenal gland volume was assessed by a 3D MR data set. The salivary cortisol was determined at 9 AM and 4 PM. Men had significantly more visceral fat and less subcutaneous fat than women. Adrenal gland size correlated significantly with the visceral and subcutaneous fat in women (r=0.7, p=0.008), but not in men (r=0.2, p=0.4). There was a negative correlation between the decrease of cortisol between 9 AM and 4 PM with VAT (r=-0.451, p=0.027) in the whole group. The high correlation between the adrenal gland volume and VAT in women underlines the link between hypothalamic-pituitary-adrenal (HPA) axis, stress, and circadian cortisol rhythm, respectively, and an increased abdominal fat volume. The lack of correlation between visceral fat and adrenal volume in men points to an additional influence of sex hormones.