Cortisol and 11 beta-hydroxysteroid dehydrogenase type 2 as potential determinants of renal citrate excretion in healthy children

BACKGROUND

In patients with Cushing disease, renal citrate excretion is reduced. A low urinary citrate concentration is a risk factor for nephrolithiasis. Since higher acid loading is one major determinant of reduced citrate excretion, we aimed to examine whether glucocorticoids still within the physiological range may already impact on urinary citrate excretion independently of acid-base status.

METHODS

Overall, 132 healthy prepubertal participants of the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study who had collected two successive 24-h urine samples (at 1 and 2 years) before the start of their pubertal growth spurt were included in the study. Net acid excretion capacity (NAEC), urinary potential renal acid load (PRAL), creatinine, calcium, and various cortisol metabolites were measured in all samples. Glucocorticoid quantification was done by GC-MS and radioimmunoassay.

RESULTS

In regression models multivariable-adjusted for 24-h urinary PRAL, NAEC, creatinine and calcium, urinary free cortisol (UFF), 6β-hydroxycortisol, and 20α-dihydrocortisol showed significant inverse relationships (P ≤ 0.02) with 24-h renal citrate output. By contrast, the estimate of renal 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), i.e., the ratio of urinary free cortisone/UFF, associated positively with urinary citrate (P = 0.04).

CONCLUSIONS

In line with studies in hypercortisolic state, even moderately high cortisol levels in healthy children, still within the physiological range, may negatively impact on the kidney's citrate excretion. Besides, a higher 11β-HSD2 activity, favoring cortisol inactivation, is paralleled by an increased citrate excretion.

Glucocorticoid activity and metabolism with NaCl-induced low-grade metabolic acidosis and oral alkalization: results of two randomized controlled trials

Low-grade metabolic acidosis (LGMA), as induced by high dietary acid load or sodium chloride (NaCl) intake, has been shown to increase bone and protein catabolism. Underlying mechanisms are not fully understood, but from clinical metabolic acidosis interactions of acid-base balance with glucocorticoid (GC) metabolism are known. We aimed to investigate GC activity/metabolism under alkaline supplementation and NaCl-induced LGMA. Eight young, healthy, normal-weight men participated in two crossover designed interventional studies. In Study A, two 10-day high NaCl diet (32 g/d) periods were conducted, one supplemented with 90 mmol KHCO3/day. In Study B, participants received a high and a low NaCl diet (31 vs. 3 g/day), each for 14 days. During low NaCl, the diet was moderately acidified by replacement of a bicarbonate-rich mineral water (consumed during high NaCl) with a non-alkalizing drinking water. In repeatedly collected 24-h urine samples, potentially bioactive-free GCs (urinary-free cortisol + free cortisone) were analyzed, as well as tetrahydrocortisol (THF), 5α-THF, and tetrahydrocortisone (THE). With supplementation of 90 mmol KHCO3, the marker of total adrenal GC secretion (THF + 5α-THF + THE) dropped (p = 0.047) and potentially bioactive-free GCs were reduced (p = 0.003). In Study B, however, GC secretion and potentially bioactive-free GCs did not exhibit the expected fall with NaCl-reduction as net acid excretion was raised by 30 mEq/d. Diet-induced acidification/alkalization affects GC activity and metabolism, which in case of long-term ingestion of habitually acidifying western diets may constitute an independent risk factor for bone degradation and cardiometabolic diseases.

Changes of Dietary Fat and Carbohydrate Content Alter Central and Peripheral Clock in Humans

CONTEXT

The circadian clock coordinates numerous metabolic processes with light-dark and feeding regimens. However, in humans it is unknown whether dietary patterns influence circadian rhythms.

OBJECTIVE

We examined the effects of switching from a high-carbohydrate, low-fat diet to a low-carbohydrate, high fat (LC/HFD) isocaloric diet on the central and peripheral circadian clocks in humans.

DESIGN

Diurnal patterns of salivary cortisol and gene expression were analyzed in blood monocytes of 29 nonobese healthy subjects before and 1 and 6 weeks after the dietary switch. For this, we established a method of rhythm prediction by 3-time point data.

RESULTS

The centrally driven cortisol rhythm showed a phase delay 1 and 6 weeks after the dietary switch to a LC/HFD as well as an amplitude increase. The dietary switch altered diurnal oscillations of core clock genes (PER1, PER2, PER3, and TEF) and inflammatory genes (CD14, CD180, NFKBIA, and IL1B). The LC/HFD also affected the expression of nonoscillating genes contributing to energy metabolism (SIRT1) and fat metabolism (ACOX3 and IDH3A). Expression of clock genes but not of salivary cortisol in monocytes tightly correlated with levels of blood lipids and with expression of metabolic and inflammatory genes.

CONCLUSIONS

Our results suggest that the modulation of the dietary fat and carbohydrate content alters the function of the central and peripheral circadian clocks in humans.

Aldosterone augments Na+-induced reduction of cardiac norepinephrine reuptake

Impairment of the cardiac norepinephrine (NE) reuptake by the neuronal NE transporter contributes to enhanced cardiac NE net release in congestive heart failure. Elevated plasma levels of aldosterone (AL) promote sympathetic overstimulation in failing hearts by unclear mechanisms. Our aim was to evaluate if elevated AL and/or alterations in Na(+) intake regulate cardiac NE reuptake. To test the effects of AL and Na(+) on cardiac NE reuptake, Wistar rats were fed a normal-salt (NS) diet (0.2% NaCl), a low-salt (LS) diet (0.015% NaCl), or a high-salt (HS) diet (8% NaCl). Another group of animals received AL infusion alone (0.75 μg/h) or AL infusion plus HS diet. Specific cardiac [(3)H]NE uptake via the NE transporter in a Langendorff preparation and AL plasma levels were measured at different time points between 5 and 42 days of treatment. To compare these findings from healthy animals with a disease model, Dahl salt-sensitive rats were investigated as a model of congestive heart failure with endogenously elevated AL. In summary, neither exogenous nor endogenous elevations of AL alone were sufficient to reduce cardiac NE reuptake. Only the HS diet induced a reduction of NE reuptake by 26%; additional infusion of AL augmented this effect to a further reduction of NE reuptake by 36%. In concordance, Dahl salt-sensitive rats treated with a HS diet displayed elevated AL and a marked reduction of NE reuptake. We conclude that exogenous or endogenous AL elevations alone do not reduce cardiac NE reuptake, but AL serves as an additional factor that negatively regulates cardiac NE reuptake in concert with HS intake.

11β Hydroxysteroid dehydrogenase type 2 and dietary acid load are independently associated with blood pressure in healthy children and adolescents

BACKGROUND

The reduced activity of 11β hydroxysteroid dehydrogenase type 2 (11βHSD2) contributes to elevated blood pressure (BP) in clinical syndromes, but its effect on BP in the physiologic range is unclear.

OBJECTIVES

We examined the association of 11βHSD2 activity with BP in healthy children independent of known BP-related dietary and other factors and determined whether the diet-dependent acid load may constitute a dietary factor related to BP.

DESIGN

We conducted a cross-sectional analysis in 267 healthy children (age range: 4-14 y) who provided a 24-h urine sample, a parallel 3-d weighed dietary record, and 1-3 BP measurements ±1.5 y around the urine collection. The ratio of urinary free cortisone to cortisol measured by using a radioimmunoassay was used as an index for 11βHSD2. Urinary net acid excretion and the urinary and dietary potential renal acid load (PRAL) were used to predict the diet-dependent acid load. The PRAL was calculated as the sum of major mineral nonbicarbonate anions minus the sum of mineral cations. Sex-, age- and height-independent SD scores (SDSs) of systolic and diastolic BP were used as outcomes in linear regression analyses.

RESULTS

11βHSD2 was inversely associated with systolic BP SDSs in basic models and in analyses adjusted for body size, maternal BP, breastfeeding, and dietary intakes of total energy, salt, and fruit and vegetables (P = 0.03). In models that included indexes of dietary acid load instead of fruit and vegetables, all 3 acid-load biomarkers were significantly (P = 0.006-0.02) directly related to systolic BP.

CONCLUSION

A lower 11βHSD2 activity and higher dietary acid load may independently contribute to higher systolic BP in healthy children.

Alkaline salts to counteract bone resorption and protein wasting induced by high salt intake: results of a randomized controlled trial

High sodium chloride (NaCl) intake can induce low-grade metabolic acidosis (LGMA) and may thus influence bone and protein metabolism. We hypothesized that oral potassium bicarbonate (KHCO(3)) supplementation may compensate for NaCl-induced, LGMA-associated bone resorption and protein losses. Eight healthy male subjects participated in a randomized trial with a crossover design. Each of two study campaigns consisted of 5 d of dietary and environmental adaptation followed by 10 d of intervention and 1.5 d of recovery. In one study campaign, 90 mmol KHCO(3)/d were supplemented to counteract NaCl-induced LGMA, whereas the other campaign served as a control with only high NaCl intake. When KHCO(3) was ingested during high NaCl intake, postprandial buffer capacity ([HCO(3)(-)]) increased (P = 0.002). Concomitantly, urinary excretion of free potentially bioactive glucocorticoids [urinary free cortisol (UFF) and urinary free cortisone (UFE)] was reduced by 14% [∑(UFF,UFE); P = 0.024]. Urinary excretion of calcium and bone resorption marker N-terminal telopeptide of type I collagen was reduced by 12 and 8%, respectively (calcium, P = 0.047; N-terminal bone collagen telopeptide, P = 0.044). There was a trend of declining net protein catabolism when high NaCl was combined with KHCO(3) (P = 0.052). We conclude that during high salt intake, the KHCO(3)-induced postprandial shift to a more alkaline state reduces metabolic stress. This leads to decreased bone resorption and protein degradation, which in turn might initiate an anticatabolic state for the musculoskeletal system in the long run.

A functional Tph2 C1473G polymorphism causes an anxiety phenotype via compensatory changes in the serotonergic system

The association of single-nucleotide polymorphisms (SNPs) in the human tryptophan hydroxylase 2 (TPH2) gene with anxiety traits and depression has been inconclusive. Observed inconsistencies might result from the fact that TPH2 polymorphisms have been studied in a genetically heterogeneous human population. A defined genetic background, control over environmental factors, and the ability to analyze the molecular and neurochemical consequences of introduced genetic alterations constitute major advantages of investigating SNPs in inbred laboratory mouse strains. To investigate the behavioral and neurochemical consequences of a functional C1473G SNP in the mouse Tph2 gene, we generated congenic C57BL/6N mice homozygous for the Tph2 1473G allele. The Arg(447) substitution in the TPH2 enzyme resulted in a significant reduction of the brain serotonin (5-HT) in vivo synthesis rate. Despite decreased 5-HT synthesis, we could detect neither a reduction of brain region-specific 5-HT concentrations nor changes in baseline and stress-induced 5-HT release using a microdialysis approach. However, using a [(35)S]GTP-γ-S binding assay and 5-HT(1A) receptor autoradiography, a functional desensitization of 5-HT(1A) autoreceptors could be identified. Furthermore, behavioral analysis revealed a distinct anxiety phenotype in homozygous Tph2 1473G mice, which could be reversed with chronic escitalopram treatment. Alterations in depressive-like behavior could not be detected under baseline conditions or after chronic mild stress. These findings provide evidence for an involvement of functional Tph2 polymorphisms in anxiety-related behaviors, which are likely not caused directly by alterations in 5-HT content or release but are rather due to compensatory changes during development involving functional desensitization of 5-HT(1A) autoreceptors.

A new transgenic rat model overexpressing the angiotensin II type 2 receptor provides evidence for inhibition of cell proliferation in the outer adrenal cortex

This study aimed to elucidate the role of the AT(2) receptor (AT(2)R), which is expressed and upregulated in the adrenal zona glomerulosa (ZG) under conditions of increased aldosterone production. We developed a novel transgenic rat (TGR; TGRCXmAT(2)R) that overexpresses the AT(2)R in the adrenal gland, heart, kidney, brain, skeletal muscle, testes, lung, spleen, aorta, and vein. As a consequence the total angiotensin II (Ang II) binding sites increased 7.8-fold in the kidney, 25-fold in the heart, and twofold in the adrenals. The AT(2)R number amounted to 82-98% of total Ang II binding sites. In the ZG of TGRCXmAT(2)R, the AT(2)R density was elevated threefold relative to wild-type (WT) littermates, whereas AT(1)R density remained unchanged. TGRCXmAT(2)R rats were viable and exhibited normal reproduction, blood pressure, and kidney function. Notably, a slightly but significantly reduced body weight and a moderate increase in plasma urea were observed. With respect to adrenal function, 24-h urinary and plasma aldosterone concentrations were unaffected in TGRCXmAT(2)R at baseline. Three and 14 days of Ang II infusion (300 ng·min(-1)·kg(-1)) increased plasma aldosterone levels in WT and in TGR. These changes were completely abolished by the AT(1)R blocker losartan. Of note, glomerulosa cell proliferation, as indicated by the number of Ki-67-positive glomerulosa cells, was stimulated by Ang II in TGR and WT rats; however, this increase was significantly attenuated in TGR overexpressing the AT(2)R. In conclusion, AT(2)R in the adrenal ZG inhibits Ang II-induced cell proliferation but has no obvious lasting effect on the regulation of the aldosterone production at the investigated stages.

Alterations in the neuroendocrinological stress response to acute psychosocial stress in adolescents engaging in nonsuicidal self-injury

OBJECTIVE

To investigate the neuroendocrinological stress response to acute psychosocial stress in a clinical sample of female adolescents engaging in nonsuicidal self-injury (NSSI).

METHODS

The Trier Social Stress Test (TSST), a standardized psychosocial stress protocol, was performed in 14 female patients who engaged in NSSI and 14 healthy control subjects. NSSI was assessed by the Functional Assessment of Self-Mutilation (FASM). Salivary cortisol, heart rate, and affective states, assessed by the Positive and Negative Affect Schedule (PANAS), were measured during the TSST.

RESULTS

We found an attenuated cortisol response to acute psychosocial stress in female adolescents with NSSI, whereas no group differences were observed in heart rate and emotional response to the TSST.

CONCLUSIONS

These findings indicate that the HPA axis is hyporesponsive in adolescents with NSSI. Therefore, reduced secretion of cortisol could play a role in promoting vulnerability of these individuals to acute stress and maladaptive stress responses.

Diagnosis of glucocorticoid-remediable aldosteronism in hypertensive children

OBJECTIVE

Glucocorticoid-remediable aldosteronism (GRA) is caused by the presence of a chimeric gene originating from an unequal cross-over between the CYP11B1 and CYP11B2 genes. Aldosterone suppression by dexamethasone and high 18-hydroxycortisol (18-OHF) levels have been used to differentiate GRA from the other forms of primary aldosteronism.

METHODS

A dexamethasone suppression test including serum 18-OHF determination and the measurement of urinary excretion of aldosterone, its metabolites and 18-OHF were performed in 3 children of a family with primary aldosteronism. Polymerase chain reactions were performed to identify the chimeric gene.

RESULTS

The chimeric gene was identified in 2 children, their mother and grandmother. The affected children had an aldosterone-to-plasma renin activity ratio >30, elevated serum 18-OHF concentration and increased urinary excretion of aldosterone, its metabolites, and 18-OHF. Post-dexamethasone concentrations of serum aldosterone and 18-OHF concentrations were suppressed.

CONCLUSION

Although very rare, the possible diagnosis of GRA should be considered in all children or young adults with low-renin hypertension. Since genetic testing is more specific than biochemical testing, a definitive diagnosis can only be obtained by identification of the CYP11B1/CYP11B2 chimeric gene.

TAK1 in brain endothelial cells mediates fever and lethargy

Expression of the MAP kinase kinase kinase TAK1 in brain endothelial cells is needed for production of prostaglandin E2, and for induction of fever and sickness behavior, in response to peripheral inflammation.

Systemic inflammation affects the brain, resulting in fever, anorexia, lethargy, and activation of the hypothalamus–pituitary–adrenal axis. How peripheral inflammatory signals reach the brain is still a matter of debate. One possibility is that, in response to inflammatory stimuli, brain endothelial cells in proximity to the thermoregulatory centers produce cyclooxygenase 2 (COX-2) and release prostaglandin E2, causing fever and sickness behavior. We show that expression of the MAP kinase kinase kinase TAK1 in brain endothelial cells is needed for interleukin 1β (IL-1β)–induced COX-2 production. Exploiting the selective expression of the thyroxine transporter Slco1c1 in brain endothelial cells, we generated a mouse line allowing inducible deletion of Tak1 specifically in brain endothelium. Mice lacking the Tak1 gene in brain endothelial cells showed a blunted fever response and reduced lethargy upon intravenous injection of the endogenous pyrogen IL-1β. In conclusion, we demonstrate that TAK1 in brain endothelial cells induces COX-2, most likely by activating p38 MAPK and c-Jun, and is necessary for fever and sickness behavior.

Prepubertal glucocorticoid status and pubertal timing

CONTEXT

Whether prepubertal glucocorticoid status impacts on the timing of puberty is not clear.

OBJECTIVE

The objective of the study was to examine the relationship between prepubertal glucocorticoid status and early or late pubertal markers, independent of adrenarchal and nutritional status.

DESIGN AND PARTICIPANTS

Prospective cohort study of healthy Caucasian children (n = 111, 56 boys) who provided both 24-h urine samples and weighed dietary records 1 and 2 yr before the start of pubertal growth spurt [age at take-off (ATO)].

MEASUREMENTS

Major urinary glucocorticoid and androgen metabolites determined by gas chromatography-mass spectrometry analysis were summed to assess daily overall cortisol (ΣC21) and adrenal androgen secretion; urinary free cortisol and cortisone measured by RIA were summed (UFF+UFE) as an indicator of potentially bioactive free glucocorticoids.

MAIN OUTCOMES

The main outcomes included ATO, age at peak height velocity, age at menarche/voice break, ages at Tanner stage 2 for breast (girls) and genital (boys) development, and pubic hair.

RESULTS

In girls ΣC21, but not UFF+UFE, was associated with pubertal markers after adjusting for overall adrenal androgen, urinary nitrogen, and body fat. Girls with higher ΣC21 (fourth quartile) reached ATO 0.7 yr (P = 0.01) and menarche 0.9 yr later (P = 0.006) than girls with lower ΣC21 (first quartile). The ΣC21 tended to be also positively associated with age at Tanner stage 2 for breast (P = 0.1), Tanner stage 2 for pubic hair (P = 0.1), and age at peak height velocity (P = 0.06). In boys, neither the ΣC21 nor UFF+UFE was related to pubertal timing.

CONCLUSION

An individually higher prepubertal glucocorticoid secretion level, even in physiological range, appears to delay early and late pubertal timing of healthy girls, particularly their onset of pubertal growth spurt and menarche.

Effects of hyperlipidaemia on glucocorticoid metabolism: results of a randomized controlled trial in healthy young women

OBJECTIVE

It is well established that the hypothalamic-pituitary-adrenal (HPA) axis is altered in obese individuals. Hyperlipidaemia with elevated levels of free fatty acids (FFAs) is also frequently seen in obesity and in the metabolic syndrome. We hypothesized, therefore, that hyperlipidaemia may alter the activity of the HPA axis.

PATIENTS AND METHODS

The effects of hyperlipidaemia, including increased circulating FFAs, on ACTH secretion and cortisol metabolism were analysed in 13 healthy young women during the early follicular phase of two subsequent cycles. We administered a 20% lipid/heparin (LHI) or a saline/heparin infusion (SHI) using a crossover design in random order for 330 min. A detailed characterization of glucocorticoid metabolism was performed by measurement of plasma ACTH, cortisol and urinary excretion rates of adrenal glucocorticoids and the glucocorticoid metabolites.

RESULTS

We observed that LHI-induced hyperlipidaemia elevated serum cortisol levels compared to SHI. No changes in plasma ACTH levels, daily urinary excretion rates of adrenal glucocorticoids, glucocorticoid precursors/metabolites and the calculated activities of the 5α-reductase, 3β-hydroxysteroid dehydrogenase (HSD), 11-, 17-, 21-hydroxylase and 11β-HSD 1 or 2 were found.

CONCLUSION

Our randomized controlled trial suggests that the adrenal sensitivity to ACTH may be enhanced by LHI-induced hyperlipidaemia in normal-weight healthy young women. This effect might contribute to the disturbances of the HPA axis described in women with abdominal obesity and impaired lipid metabolism.

Urine volume dependency of specific dehydroepiandrosterone (DHEA) and cortisol metabolites in healthy children

Urine volume should be considered as a confounder when using urinary free cortisol (UFF) and cortisone (UFE) to assess glucocorticoid (GC) status. We aimed to examine whether adrenal androgen (AA) metabolites may be also affected by urine volume in healthy children. To compare the flow dependence of GC and AA metabolites, specific GC metabolites were examined. In 24-h urine samples of 120 (60 boys) healthy children (4-10 yr), steroid profiles were determined by GC-MS analysis, UFF and UFE by radioimmunoassay. To assess daily AA and GC secretion rates, 7 quantitatively most important AA (∑C19) and GC (∑C21) metabolites were summed. Sum of DHEA and its 16α-hydroxylated metabolites were denoted as DHEA&M. Association of urine volume with AA (∑C19, DHEA&M, DHEA, 16α-hydroxy-DHEA, 3β,16α,17β-androstenetriol) and GC (∑C21, UFF, UFE, 6β-hydroxycortisol, 20α-dihydrocortisol) were examined in linear regression models. Among the examined AA metabolites, 16α-hydroxy-DHEA (β=0.56, p<0.0001) and DHEA (β=0.43, p=0.05) showed relatively strong association with urine volume. A trend was seen for ∑C19 (β=0.23, p=0.08), but not for DHEA&M (p>0.1). Regarding GC metabolites, urine volume showed a stronger association with cortisol's direct metabolites, i.e., cortisone, 6β-hydroxycortisol and 20α-dihydrocortisol (β=0.4-0.6, p<0.01) than with cortisol itself (β=0.28, p<0.05). ∑C21 was not associated with urine volume. In conclusion, like UFF and UFE, renal excretion of DHEA, 16α-hydroxy-DHEA, 6β-hydroxycortisol, and 20α-dihydrocortisol may also depend on urine volume. The intrarenal production of the latter three and cortisone might explain their relative strong water-flow-dependency. Total AA or GC secretion marker appears not to be relevantly confounded by urine volume.

Brief review: glucocorticoid excretion in obesity

Cortisol secretion and glucocorticoid excretion rates are regularly increased in obesity and associate with indices of body size and visceral adiposity. Different mechanisms may underlie the elevated urinary excretion rates of cortisol metabolites in obesity. In the present brief overview, potential mechanisms are discussed, paying special attention to cortisol metabolism. Besides, potential confounding factors in the evaluation of urinary glucocorticoid excretion are highlighted.

Prepubertal adrenarchal androgens and animal protein intake independently and differentially influence pubertal timing

CONTEXT

Whether adrenarche impacts on pubertal development is controversial.

OBJECTIVE

The objective of the study was to examine the associations of adrenal androgen (AA) secretion with early and late pubertal markers, independent of potential influences of dietary animal protein intake.

DESIGN AND PARTICIPANTS

This was a prospective cohort study of healthy free-living Caucasian children (n = 109) who provided both 24-h urine samples and 3-d weighed dietary records 1 and 2 yr before the biological age at take-off of the pubertal growth spurt (ATO).

MEASUREMENTS

Twenty-four-hour excretion rates of androgen (C19) metabolites quantified by gas chromatography-mass spectrometry were measured.

MAIN OUTCOMES

ATO, age at peak height velocity (APHV), age at menarche/voice break, duration of pubertal growth acceleration, and ages at Tanner stage 2 for breast (girls) and genital (boys) development (B2-G2) and pubic hair (PH2).

RESULTS

Higher adrenarchal C19 steroids predicted earlier ages at Tanner stage 2 for pubic hair (P < 0.0001) and B2-G2 (P = 0.009) as well as a shorter pubertal growth acceleration period (P = 0.001), independently of animal protein intake. Children with a higher AA secretion had a 1.5-yr earlier beginning of pubarche and a 0.8-yr earlier beginning of B2-G2 than those with a lower AA excretion. Furthermore, animal protein intake was independently negatively associated with ATO and APHV (P < 0.05 each) and tended to be negatively associated with age at menarche/voice break (P = 0.07).

CONCLUSION

A higher animal protein intake may be involved in an earlier attainment of ATO and APHV, whereas a more intensive adrenarchal process may precipitate a shorter pubertal growth spurt and a notably earlier onset of breast and genital development in girls and boys, respectively.

Blockade of tachykinin NK1/NK2 receptors in the brain attenuates the activation of corticotrophin-releasing hormone neurones in the hypothalamic paraventricular nucleus and the sympathoadrenal and pituitary-adrenal responses to formalin-induced pain in the rat

Evidence from pharmacological studies has implicated substance P (SP), a natural ligand of tachykinin NK(1) receptors which can also interact with NK(2) receptors, in the generation of pressor and tachycardic responses to stress. Using selective blockade of brain NK(1) and NK(2) receptors, we tested in conscious rats the hypothesis that SP initiates, within the neuronal brain circuits, the sympathoadrenal, hypothalamic-pituitary-adrenal (HPA) and behavioural responses to noxious stimuli. Formalin injected s.c. through a chronically implanted catheter in the area of the lower leg was used as a pain stimulus. Rats were pretreated i.c.v. with vehicle or the selective, nonpeptide antagonists of tachykinin NK(1) and NK(2) receptors, RP 67580 and SR 48968, respectively. Ten minutes thereafter, formalin was injected s.c. and the cardiovascular responses were recorded, plasma concentrations of catecholamines, adrenocorticotrophic hormone (ACTH) and corticosterone were determined and the expression of the inducible transcription factor c-Fos in the paraventricular (PVN) and supraoptic nuclei was detected to identify neurones which were activated during pain stimulation. Blockade of NK(1) and NK(2) receptors attenuated the formalin-induced increases in mean arterial pressure and heart rate, adrenaline and ACTH concentrations in plasma, and completely abolished the pain-induced c-Fos expression in corticotrophin-releasing hormone neurones localised in the parvocellular division of the PVN. The results obtained provide pharmacological evidence that tachykinins, most probably SP, act as mediators within the neuronal circuits linked to the initiation and control of the cardiovascular, sympathoadrenal, HPA and behavioural responses to pain stimuli and provide an excitatory input to corticotrophin-releasing hormone neurones in the PVN to activate the HPA axis. Our data demonstrating the inhibition of the complex response pattern to noxious stimuli and stress are consistent with the proposed anxiolytic and antidepressant activity of NK(1) and NK(2) receptor antagonists.

Expression of the kcnk3 potassium channel gene lessens the injury from cerebral ischemia, most likely by a general influence on blood pressure

We examined the possible protective effect of TASK-1 (TWIK-related acid-sensitive potassium channel-1, kcnk3) and -3 potassium channels during stroke. TASK-1 and TASK-3, members of the two pore domain (K2P or kcnk) potassium channel family, form hetero or homodimers and help set the resting membrane potential. We used male TASK-1 and TASK-3 knockout mice in a model of focal cerebral ischemia, permanent middle cerebral artery occlusion (pMCAO). Infarct volume was measured 48 h after pMCAO. The TASK-1 knockout brains had larger infarct volumes (P=0.004), and those in TASK-3 knockouts were unchanged. As the TASK-1 gene is expressed in adrenal gland, heart and possibly blood vessels, the higher infarct volumes in the TASK-1 knockout mice could be due to TASK-1 regulating blood vessel tone and hence blood pressure or influencing blood vessel microarchitecture and blood flow rate. Indeed, we found that male TASK-1 knockout mice had reduced blood pressure, likely explaining the increased brain injury seen after pMCAO. Thus to make precise conclusions about how TASK-1 protects neurons, neural- or organ-specific deletions of the gene will be needed. Nevertheless, a consequence of having TASK-1 channels expressed (in various non-neuronal tissues and organs) is that neuronal damage is lessened when stroke occurs.

Glucocorticoids and body fat associated with renal uric acid and oxalate, but not calcium excretion, in healthy children

In patients with hypercortisolism, who are frequently obese, the prevalence of elevated urinary excretion rates of the potential lithogenic factors (calcium, oxalate, and uric acid) is increased. We examined whether the 24-hour urinary excretion rates of calcium, oxalate, and uric acid are already associated with body fat and endogenous glucocorticoids in healthy free-living children, taking relevant nutritional and acid-base factors into account. Urinary analyte excretions were determined in 24-hour urine samples of 300 healthy children aged 4 to 14 years. Potentially bioactive free glucocorticoids were assessed as urinary free cortisol + urinary free cortisone. Associations of glucocorticoids and percentage body fat with the outcome variables were examined in regression models adjusted for sex, height, growth velocity, urinary volume, net acid excretion, and relevant nutritional factors. Percentage body fat and urinary free cortisol + urinary free cortisone explained most of the growth-independent variation of urinary uric acid and also a relevant part of oxalate, but none of calcium. Net acid excretion, an indicator of endogenous acid production, and dietary protein, salt, and fiber intakes were also variably associated with the outcomes urinary calcium, oxalate, and uric acid. In conclusion, body fatness and potentially bioactive free glucocorticoids (even in the physiologic range) appear to affect urinary excretion rates of oxalate and uric acid, whereas urinary calcium output is more strongly related to dietary factors in healthy children. Our data provide the first in vivo-based evidence that the obesity- or hypercortisolism-associated urolithiasis may be a pathophysiologic continuation of the corresponding endocrine metabolic variations in healthy children.

Neuroendocrine function following traumatic brain injury and subsequent intensive care treatment: a prospective longitudinal evaluation

Neuroendocrine dysfunction following traumatic brain injury (TBI) has been described extensively. However, few studies are longitudinal and most lack subtle radiological, clinical, and repetitive endocrine assessment in the acute phase. Accordingly, we prospectively assessed neuroendocrine function in 71 patients after TBI. Injury was documented by a computed tomography (CT). During the first week, critical clinical data (Glasgow Coma Score, APACHE score), treatment variables such as duration of analgosedation for mechanical ventilation, were related to basal pituitary function. More than 2 years later, a subgroup of patients was re-evaluated using dynamic testing with ACTH and GHRH-arginine tests. The Pearson's correlation analysis and Mann-Whitney rank sum test for group differences were used for statistical analysis. None of the CT findings predicted neuroendocrine dysfunction following TBI. The adaptive response to critical illness with significantly elevated cortisol levels on admission and decreased levels thereafter in patients ventilated for more than 24 h (p < 0.05) was attenuated following severe TBI (p < 0.05). However, the coincidence of low serum cortisol and increased urinary excretion of glucocorticoid metabolites in about 80% of patients challenges the relevance of basal hormone measurements. In ventilated patients, total T3 and free T4 were decreased (p < 0.05), TSH was low on day 3 (p < 0.05), and a gonadotropic insufficiency was present (p < 0.05). The thyrotropic and gonadotropic system recovered completely within the follow-up period. With regard to the somatotropic system, neither brain injury severity nor mechanical ventilation was associated with an insufficiency during the acute phase post-injury. However, initially low GH levels predicted a persistent deficiency (r = 0.731, p < 0.001). We conclude that both severe TBI and prolonged mechanical ventilation result in hormonal disturbances early after injury, suggesting a pathophysiological response to brain injury and subsequent intensive care treatment rather than morphological damage.

Saliva as a medium for aldosterone measurement in repeated sampling studies

BACKGROUND

Saliva is a readily available biological fluid, making it convenient in diagnosis of diseases and in multi-sampling protocols. Several salivary steroids give a useful index of free plasma levels. Increased incidence of primary aldosteronism (PA) in approximately 10% of the hypertensive population has increased interest in the mineralocorticoid aldosterone.

METHODS

A biotinylated-aldosterone tracer and a commercially available antibody are used in a time-resolved fluorescence immunoassay (TR-FIA) to measure salivary aldosterone (SA). Saliva was collected in various multi-sampling protocols: Investigation of diurnal rhythm in healthy and PA patients, ACTH stimulation test and posture test in healthy subjects.

RESULTS

Method validation showed a sensitivity of 19 ng/L and intra-/inter-assay precision between 7.2-10.1% and 8.7-15.7%, respectively. SA correlated significantly (y = 0.2995x +/- 0.01, r(2)=0.60) to plasma aldosterone measured by a commercial radioimmunoassay. SA (median; 95%CI) was at 111 (95-127)ng/L in PA (n=84) and 50 (44-56)ng/L in healthy subjects (n=60). After change in posture, aldosterone increased in both, saliva (57 (47-63)ng/L to 95 (84-117)ng/L) and plasma (26 (26-41)ng/L to 135 (110-181)ng/L). Peak levels were reached after 1h, and were higher in females than in males.

CONCLUSIONS

SA correlates well to plasma aldosterone and mirrors responses during conditions of stress. SA is significantly higher in PA, and the diurnal rhythm seen in the healthy is blunted in PA. We additionally found gender-dependent differential responses to posture, with higher increases in females. Measurement of aldosterone in saliva presents a useful and convenient method for application in multi-sampling studies.

Urinary free cortisone, but not cortisol, is associated with urine volume in severe obesity

BACKGROUND

High urine volume enhances urinary free cortisol (UFF) and cortisone (UFE) excretion rates in normal-weight adults and children. Renal excretion rates of glucocorticoids (GC) and their metabolites are frequently altered in obesity. The aim of the present study was to investigate whether UFF and UFE excretion is also affected by urine volume in severely obese subjects.

EXPERIMENTAL

In 24-h urine samples of 59 extremely obese subjects (mean BMI 45.3+/-8.9 kg/m(2)) and 20 healthy lean subjects (BMI 22.1+/-1.8 kg/m(2)), UFF and UFE, tetrahydrocortisol (THF), 5alpha-tetrahydrocortisol (5alpha-THF), and tetrahydrocortisone (THE) were quantified by RIA. The sum of THF, 5alpha-THF, and THE (GC3), the three major GC metabolites, reflects daily cortisol secretion. 11beta-Hydroxysteroid dehydrogenase type 2 (11beta-HSD2) activity was assessed by the ratio UFE/UFF. Daily GC excretion rates were corrected for urine creatinine and adjusted for gender and body weight.

RESULTS

In extremely obese subjects, urine volume was significantly associated with creatinine-corrected UFE and 11beta-HSD2 activity after adjustment for gender and BMI (r=0.47, p=0.0002 and r=0.31, p=0.02, respectively). However, urine volume was not associated with creatinine-corrected UFF and GC3 (p=0.4 and p=0.6, respectively). In lean controls, urine volume was significantly associated with creatinine-corrected UFE and UFF (r=0.58, p=0.01 and r=0.55, p=0.02, respectively), whereas urine volume was not associated with 11beta-HSD2 activity after appropriate adjustment (p=0.3).

CONCLUSIONS

In severe obesity, in contrast to normal weight, renal excretion of UFE, but not of UFF is affected by fluid intake. This discrepancy may be due to the increased renal 11beta-HSD2 activity in obesity.

Daily urinary free cortisol and cortisone excretion is associated with urine volume in healthy children

BACKGROUND

In experimental studies, a high fluid intake and a corresponding high urine volume have been shown to increase renal excretion rates of urinary free cortisol (UFF) and cortisone (UFE) in adults. We aimed to examine whether 24-h UFF and UFE excretion rates are also affected by urine volume in children.

METHODS

In 24-h urine samples of 100 pre-pubertal and 100 pubertal healthy children UFF, UFE, tetrahydrocortisol (THF), 5alpha-tetrahydrocortisol (5alpha-THF), and tetrahydrocortisone (THE) were quantified by RIA. The sum of THF, 5alpha-THF, and THE, the 3 primarily glucuronidated tetrahydrometabolites (GC3), reflects daily cortisol secretion. Associations of urine volume with outcome variables UFF, UFE, and GC3 were examined in both developmental groups using multiple regression models adjusted for sex, body weight and height.

RESULTS

Significant positive associations were observed between 24-h urine volume and UFF and UFE in both groups with the highest explained variation for UFE [partial R(2)=0.11 in pre-pubertal group (P<0.005); partial R(2)=0.15 in pubertal group (P<0.0001)]. However, for outcome GC3, urine volume was not significant in either of the groups.

CONCLUSION

Urinary 24-h excretion rates of UFF and UFE but not of the marker of glucocorticoid secretion are affected by daily urine volume in healthy free-living children. For a specific assessment of associations of UFF and UFE with (patho)physiologically relevant factors, urine volume should be considered as a confounder.

Serum concentrations of cortisol and cortisone in healthy dogs and dogs with pituitary-dependent hyperadrenocorticism treated with trilostane

The serum concentrations of cortisol and cortisone were measured in 19 healthy dogs and in 13 dogs with pituitary-dependent hyperadrenocorticism (PDH) before and one hour after an injection of synthetic adrenocorticotropic hormone (ACTH). In the dogs with pdh, the cortisol and cortisone concentrations were measured before and after one to two weeks and three to seven weeks of treatment with trilostane. The dogs with PDH had significantly higher baseline and poststimulation concentrations of cortisol and cortisone, and higher baseline cortisol:cortisone ratios than the healthy dogs. During the treatment with trilostane, the poststimulation cortisol, the baseline and poststimulation cortisone concentrations, and the baseline and poststimulation cortisol:cortisone ratios decreased significantly. The decrease in poststimulation cortisone was significantly smaller than the decrease in cortisol.

Intravenous lipid and heparin infusion-induced elevation in free fatty acids and triglycerides modifies circulating androgen levels in women: a randomized, controlled trial

BACKGROUND

The polycystic ovarian syndrome (PCOS) is characterized by hyperandrogenism and associated with obesity and impaired glucose metabolism. Despite the high prevalence of PCOS and the considerable clinical impact, the precise interplay between metabolism and hyperandrogenemia is not entirely clear.

OBJECTIVE

The objective of the study was to analyze the effects of iv lipid and heparin infusion on circulating androgen levels in healthy women.

DESIGN

This was a randomized, controlled, crossover trial.

SETTING

The study was conducted at an endocrinology center.

PATIENTS

Patients included 12 healthy young women during the early follicular phase of two subsequent cycles.

INTERVENTION

After an overnight fast, a 20% lipid/heparin or a saline/heparin infusion was administered in random order for 330 min.

MAIN OUTCOME MEASURES

A detailed characterization of androgen metabolism was performed.

RESULTS

Elevations in free fatty acids and triglycerides, induced by lipid/heparin infusion, elevates the levels of androstenedione, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), testosterone, 5alpha-dihydrotestosterone, estrone, and 17beta-estradiol. Urinary excretion of DHEA, DHEAS, 5-androstene-3beta,17beta-diol, and the sum of urinary excreted DHEA and its 16-hydroxylated downstream metabolites, 16alpha-hydroxy-DHEA and 5-androstene-3beta,16alpha,17beta-triol, were reduced.

CONCLUSION

The mechanism of iv lipid and heparin infusion-induced elevation of circulating androgens described here might contribute to the development of hyperandrogenism in women with PCOS and suggests that lowering of hyperlipidemia might be a potential therapeutic target in patients with PCOS to treat hyperandrogenemia.

11beta-hydroxysteroid dehydrogenase 2 activity is elevated in severe obesity and negatively associated with insulin sensitivity

Alterations in glucocorticoid (GC) metabolism may contribute to the development of obesity and insulin resistance. We aimed to study the role of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) in human adiposity, paying special attention to the association between altered GC metabolism and insulin sensitivity. In 24-h urine samples of 72 extremely obese (mean BMI 45.5 +/- 1.1 kg/m(2)), but otherwise healthy patients urinary free cortisol (UFF), urinary free cortisone (UFE), tetrahydrocortisol (THF), 5alpha-tetrahydrocortisol (5alpha-THF), and tetrahydrocortisone (THE) were quantified by radioimmunoassay. The sum of the three major tetrahydrometabolites is an estimate for daily GC secretion, and the sum of UFF and UFE represents potentially bioactive-free-GCs. Thirty healthy lean subjects (BMI 22.3 +/- 0.3 kg/m(2)) served as controls. In obese subjects, absolute daily GC secretion and the potentially bioactive-free-GCs were significantly (P < 0.005) higher than in lean controls (11.8 +/- 0.7 vs. 8.0 +/- 0.6 mg/d; and 171.8 +/- 11.2 vs. 117.6 +/- 9.2 mug/d, respectively). However, when these values were corrected for body surface area (BSA), significant differences were no longer detectable. While enzyme activity indices for 5alpha-reductase and 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) were similar in lean and obese subjects, 11beta-HSD2 was markedly elevated in adiposity (3.7 +/- 0.2 vs. 2.1 +/- 0.1; P < 0.0001). This increase was accompanied by a significant reduction in UFF excretion corrected for BSA (16.5 +/- 1.2 vs. 21.7 +/- 2.0 mug/d/m(2); P = 0.0222). Besides, 11beta-HSD2 activity was significantly correlated with insulin sensitivity (P = 0.0262). When body size is accounted for, both adrenal GC secretion and potentially bioactive-free-GCs are indistinguishable between lean and extremely obese subjects. However in obesity, the kidney appears to intensify its supply of the direct substrate cortisone for extrarenal 11beta-HSD1, which may fuel visceral adiposity and insulin resistance.

Selective and protracted effect of nifedipine on fear memory extinction correlates with induced stress response

Memory extinction, defined as a decrease of a conditioned response as a function of a non-reinforced conditioned stimulus presentation, has high biological and clinical relevance. Extinction is not a passive reversing or erasing of the plasticity associated with acquisition, but a novel, active learning process. Nifedipine blocks L-type voltage gated calcium channels (LVGCC) and has been shown previously to selectively interfere with the extinction, but not the acquisition, of fear memory. We studied here the effect of retrograde and anterograde shifts of nifedipine application, with respect to an extinction training, on the extinction of fear conditioning. Subcutaneous injection of 30 mg/kg nifedipine, at least up to 4 h before the extinction session, significantly impaired extinction, as did intraperitoneal injection of 15 mg/kg nifedipine, at least up to 2 h before extinction training. However, the injection of nifedipine also induced a strong and protracted stress response. The pharmacokinetics of nifedipine suggest that it was mainly this stress response that triggered the specific inhibition of extinction, not the blockade of LVGCC in the brain. Our results support recent findings that stress selectively interferes with the extinction, but not the acquisition, of fear memory. They also indicate that a pharmacological approach is not sufficient to study the role of brain LVGCC in learning and memory. Further research using specific genetically modified animals is necessary to delineate the role of LVGCC in fear memory extinction.

Renal net acid excretion and plasma leptin are associated with potentially bioactive free glucocorticoids in healthy lean women

Primarily experimental evidence suggests that endogenous glucocorticoids may be suppressed by adipocyte-derived leptin and elevated by dietary acidity. Therefore, we examined whether these factors may also be relevant in healthy adults on unrestricted diets. For this we used a new methodological approach in which potentially bioactive free glucocorticoids were determined as the sum of urinary free cortisol and urinary free cortisone and that also takes into account total adrenal glucocorticoid secretion assessed by the sum of the 3 major urinary glucocorticoid metabolites tetrahydrocortisone, tetrahydrocortisol, and 5alpha-tetrahydrocortisol. Body composition, plasma cortisol, plasma leptin, and 24-h urinary excretion rates of net acid and glucocorticoid metabolites were examined cross-sectionally in 30 healthy adults (15 women; 22-44 y old; BMI 20-25 kg/m2). Plasma leptin, percentage body fat, and body surface area-corrected adrenal glucocorticoid secretion showed the usual sex dimorphism (male vs. female, P < 0.05 in each case: 2.8 +/- 1.6 microg/L vs. 7.6 +/- 4.9 microg/L, 16.8 +/- 4.2% vs. 26.9 +/- 4.9%, and 5.1 +/- 1.6 mg x m(-2) x d(-1) vs. 4.0 +/- 1.3 mg x m(-2) x d(-1), respectively), whereas net acid excretion, plasma cortisol, and potentially bioactive free glucocorticoids did not differ between the sexes. Potentially bioactive free glucocorticoids correlated positively with body fat and leptin in men (P < 0.05) but not in women. After adjustment for total adrenal glucocorticoid secretion, net acid excretion was a positive and leptin a negative predictor (P < 0.05) of potentially bioactive free glucocorticoids in women only (total explained variability R2 = 0.71). Our findings indicate that, at least in women, variability of potentially bioactive free glucocorticoids is not only explained by adrenal glucocorticoid secretion but is also metabolically affected by circulating leptin and diet-dependent net acid excretion.

G12-G13-LARG-mediated signaling in vascular smooth muscle is required for salt-induced hypertension

The tone of vascular smooth muscle cells is a primary determinant of the total peripheral vascular resistance and hence the arterial blood pressure. Most forms of hypertension ultimately result from an increased vascular tone that leads to an elevated total peripheral resistance. Regulation of vascular resistance under normotensive and hypertensive conditions involves multiple mediators, many of which act through G protein-coupled receptors on vascular smooth muscle cells. Receptors that mediate vasoconstriction couple with the G-proteins G(q)-G11 and G12-G13 to stimulate phosphorylation of myosin light chain (MLC) via the Ca2+/MLC kinase- and Rho/Rho kinase-mediated signaling pathways, respectively. Using genetically altered mouse models that allow for the acute abrogation of both signaling pathways by inducible Cre/loxP-mediated mutagenesis in smooth muscle cells, we show that G(q)-G11-mediated signaling in smooth muscle cells is required for maintenance of basal blood pressure and for the development of salt-induced hypertension. In contrast, lack of G12-G13, as well as of their major effector, the leukemia-associated Rho guanine nucleotide exchange factor (LARG), did not alter normal blood pressure regulation but did block the development of salt-induced hypertension. This identifies the G12-G13-LARG-mediated signaling pathway as a new target for antihypertensive therapies that would be expected to leave normal blood pressure regulation unaffected.

Rosiglitazone decreases 11beta-hydroxysteroid dehydrogenase type 1 in subcutaneous adipose tissue

OBJECTIVE

The peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist rosiglitazone increases insulin sensitivity, which, in animal models, is comparable to the effect of a reduction in 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) activity. We therefore investigated whether rosiglitazone-induced insulin sensitivity is associated with changes in 11beta-HSD1 activity in different tissues.

METHODS

An oral glucose tolerance test (OGTT) and a euglycaemic hyperinsulinaemic clamp were performed in seven male volunteers [age 59.3 +/- 3.0 years, body mass index (BMI) 29.3 +/- 4.1 kg/m(2)] with impaired glucose tolerance before and after 8 weeks of rosiglitazone treatment. To assess hepatic 11beta-HSD1 activity, serum cortisol levels were measured after oral administration of cortisone acetate. 11beta-HSD1 activity and mRNA expression were assessed in abdominal subcutaneous fat biopsies. Total-body 11beta-HSD activities were estimated by calculating the urinary ratios of glucocorticoid metabolites.

RESULTS

As expected, rosiglitazone improved insulin resistance and postprandial hyperglycaemia. In parallel, 11beta-HSD1 mRNA expression [100 +/- 0% (reference) vs. 68.5 +/- 9.3%, P < 0.01] and activity [0.18 +/- 0.02 vs. 0.13 +/- 0.02 pmol/min/mg, P < 0.05] decreased in abdominal subcutaneous fat, while an increase in hepatic 11beta-HSD1 activity was detected [the area under the curve (AUC) for the cortisol/cortisone ratio was 1319 +/- 76 vs. 955 +/- 59; P < 0.05]. No changes in BMI, waist-to-hip ratio (WHR) and whole-body 11beta-HSD1 activity were found.

CONCLUSIONS

Part of the beneficial effects of rosiglitazone may be mediated by a reduction in the 11beta-HSD1 mRNA expression and activity in subcutaneous abdominal fat.

[68-year-old female patient with dyspnea and hypokalemic hypertension]

Ectopic ACTH syndrome is a rare differential diagnosis of hypokalemic hypertension. Patients with ectopic ACTH syndrome due to small cell lung cancer have a poor prognosis. We report on a 68-year-old female patient who presented with dyspnea and hypokalemic hypertension. Endocrine testing was consistent with ectopic ACTH syndrome due to small cell lung cancer. After initiation of chemotherapy with etoposide and carboplatin ACTH and cortisol levels normalized and clinical symptoms impressively improved.

Neuronal NF-kappaB influences thermoregulation and survival in a sepsis model

Gene regulation in sepsis is known to be controlled by the transcription factor NF-kappaB. However, the function of neuronal NF-kappaB in sepsis is not well defined. In a mouse model of sepsis induced by i.p. injection of lipopolysaccharides (LPS), we found an activation of NF-kappaB in the brain as shown by the induction of a transgenic NF-kappaB reporter. Inhibition of neuronal NF-kappaB by cell-specific expression of the NF-kappaB super-repressor IkappaBalpha-SR improved LPS-induced hypothermia and survival but had no effect on body weight or on the humoral response to LPS. In contrast, glial inhibition of NF-kappaB did not influence body temperature and survival. By immunohistochemistry, we detected the active NF-kappaB subunit RelA in neuronal nuclei of the organum vasculosum of the lamina terminalis. Our data reveal an important role of neuronal NF-kappaB in thermoregulation and survival. The upcoming group of NF-kappaB inhibitors may have a place in the treatment of the acute-phase response.

Growth analysis of the mouse adrenal gland from weaning to adulthood: time- and gender-dependent alterations of cell size and number in the cortical compartment

The adrenal gland is of critical importance for a plethora of biological processes. We performed the first systematic analysis of adrenal gland growth using unbiased stereological methods in male and female mice from weaning to adulthood (weeks 3, 5, 7, 9, and 11) at the organ, compartment, and cellular levels. Adrenal weights increased from week 3 to week 7 in male and female mice, remained at this level in females, but decreased by 25% between week 7 and week 9 in males. Female adrenal glands displayed a higher weight at any stage investigated. The volume of the zona fasciculata was consistently higher in female vs. male mice. In both genders, the number of zona fasciculata cells reached a maximum at the age of 7 wk and decreased significantly until week 9. Serum corticosterone concentrations decreased from 3 to 11 wk of age both in male and female mice. However, the estimated total amounts of corticosterone in the circulation were similar in 3- and 11-wk-old mice. Furthermore, total circulating corticosterone was higher in females than in males at an age of 5 and 11 wk. In the zona glomerulosa and in the X-zone, time- and gender-dependent growth effects were observed. In conclusion, our results demonstrate that growth and function of the adrenal glands are markedly influenced by gender and age. These factors require careful consideration in studies aiming at the functional dissection of genetic and environmental factors affecting adrenal growth and function.