Adrenal 11-beta hydroxysteroid dehydrogenase activity in response to stress

Perfluorotetradecanoic acid exposure to adult male rats stimulates corticosterone biosynthesis but inhibits aldosterone production

Perfluorotetradecanoic acid (PFTeDA) is a novel perfluoroalkyl substance that ubiquitously exists in the environment. However, whether PFTeDA affects adrenal cortex function remains unclear. Male Sprague-Dawley rats (age of 60 days) were daily administered with PFTeDA (0, 1, 5, and 10 mg/kg body weight) through gavage for 28 days. PFTeDA did not change body and adrenal gland weights. PFTeDA markedly elevated serum corticosterone level at 10 mg/kg but lowering serum aldosterone level at this dosage without influencing serum adrenocorticotropic hormone level. PFTeDA thickened zona fasciculata without affecting zona glomerulosa. PFTeDA remarkably upregulated the expression of corticosterone biosynthetic genes (Mc2r, Scarb1, Star, Cyp21, Cyp11b1, and Hsd11b1) and their proteins, whereas downregulating aldosterone biosynthetic enzyme Cyp11b2 and its protein, thereby distinctly altering their serum levels. PFTeDA markedly downregulated the expression of antioxidant genes (Sod1 and Sod2) and their proteins at 10 mg/kg. PFTeDA significantly decreased SIRT1/PGC1α and AMPK signaling while stimulating AKT1/mTOR signaling. Corticosterone significantly inhibited testosterone production by adult Leydig cells at >0.1 μM in vitro; however aldosterone significantly stimulated testosterone production at 0.1 nM. In conclusion, exposure to PFTeDA at male rat adulthood causes corticosterone excess and aldosterone deficiency via SIRT1/PGC1α, AMPK, and AKT1/mTOR signals, which in turn additively leads to testosterone deficiency.

Effects of bis (2-butoxyethyl) phthalate on adrenocortical function in male rats in puberty partially via down-regulating NR5A1/NR4A1/NR4A2 pathways

Phthalates may interfere with the biosynthesis of steroid hormones in the adrenal cortex. Bis (2-butoxyethyl) phthalate (BBOP) is a phthalate containing oxygen atoms in the alcohol moiety. In this study, 35-day-old male Sprague-Dawley rats were daily gavaged with BBOP (0, 10, 100, 250, and 500 mg/kg body weight) for 21 days. BBOP did not affect the weight of body and adrenal glands. BBOP significantly reduced serum corticosterone levels at 250 and 500 mg/kg, and lowered aldosterone level at 500 mg/kg without affecting adrenocorticotropic hormone. BBOP did not alter the thickness of the adrenal cortex. BBOP significantly down-regulated the expression of steroidogenesis-related genes (Scarb1, Star, Cyp11a1, Cyp21, Cyp11b1, Cyp11b2, Nr5a1, Nr4a1, and Nr4a2) and proteins, and antioxidant enzymes (Sod1, Sod2, Gpx1, and Cat) and their proteins, while up-regulating the expression of Mc2r and Agtr1a at various doses. BBOP reduced the phosphorylation of AKT1, AKT2, and ERK1/2, as well as the levels of SIRT1 and PGC1α without affecting the phosphorylation of AMPK. BBOP significantly induced the production of reactive oxygen species and apoptosis rate in H295R cells at 100 μM and higher after 24 h of treatment. In conclusion, male rats exposed to BBOP in puberty have significant reduction of steroid biosynthesis with a potential mechanism that is involved in the decrease in the phosphorylation of AKT1, AKT2, ERK1/2, as well as SIRT1 and PGC1α and increase in ROS.

11ß hydroxysteroid dehydrogenases regulate circulating glucocorticoids but not central gene expression

Regulation of glucocorticoids (GCs), important mediators of physiology and behavior at rest and during stress, is multi-faceted and dynamic. The 11ß hydroxysteroid dehydrogenases 11ß-HSD1 and 11ß-HSD2 catalyze the regeneration and inactivation of GCs, respectively, and provide peripheral and central control over GC actions in mammals. While these enzymes have only recently been investigated in just two songbird species, central expression patterns suggest that they may function differently in birds and mammals, and little is known about how peripheral expression regulates circulating GCs. In this study, we utilized the 11ß-HSD inhibitor carbenoxolone (CBX) to probe the functional effects of 11ß-HSD activity on circulating GCs and central GC-dependent gene expression in the adult zebra finch (Taeniopygia guttata). Peripheral CBX injection produced a marked increase in baseline GCs 60 min after injection, suggestive of a dominant role for 11ß-HSD2 in regulating circulating GCs. In the adult zebra finch brain, where 11ß-HSD2 but not 11ß-HSD1 is expressed, co-incubation of micro-dissected brain regions with CBX and stress-level GCs had no impact on expression of several GC-dependent genes. These results suggest that peripheral 11ß-HSD2 attenuates circulating GCs, whereas central 11ß-HSD2 has little impact on gene expression. Instead, rapid 11ß-HSD2-based regulation of local GC levels might fine-tune membrane GC actions in brain. These results provide new insights into the dynamics of GC secretion and action in this important model organism.

Low glucocorticoids in stress-related disorders: the role of inflammation

There is evidence that plasma cortisol concentration can be either increased or decreased in patients with depression and related anxiety and stress-related disorders; the exact pathophysiological mechanisms of this state are not almost clear. Several distinct theories were proposed and mechanisms, which could lead to decreased glucocorticoid signaling and/or levels, were described. However, there is a possible drawback in almost all the theories proposed: insufficient attention to the inflammatory process, which is undoubtedly present in several stress-related disorders, including post-traumatic stress disorder (PTSD). Previous studies only briefly mentioned the presence of an inflammatory reaction's signs in PTSD, without giving it due importance, although recognizing that it can affect the course of the disease. With that, the state of biochemical changes, characterized by the low glucocorticoids, glucocorticoid receptor's resistance and the signs of the persistent inflammation (with the high levels of circulating cytokines) might be observed not only in PTSD but in coronary heart diseases and systemic chronic inflammatory diseases (rheumatoid arthritis) as well. That is why the present review aims to depict the pathophysiological mechanisms, which lead to a decrease in glucocorticoids in PTSD due to the action of inflammatory stimuli. We described changes in the glucocorticoid system and inflammatory reaction as parts of an integral system, where glucocorticoids and the glucocorticoid receptor reside at the apex of a regulatory network that blocks several inflammatory pathways, while decreased glucocorticoid signaling and/or level leads to unchecked inflammatory reactions to promote pathologies such as PTSD. LAY SUMMARY This review emphasizes the importance of inflammatory reaction in the development of puzzling conditions sometimes observed in severe diseases including post-traumatic stress disorder - the decreased levels of glucocorticoids in the blood. Following the classical concepts, one would expect an increase in glucocorticoid hormones, since they are part of the feedback mechanism in the immune system, which reduces stress and inflammation. However, low levels of glucocorticoid hormones are also observed. Thus, this review describes potential mechanisms, which can lead to the development of such a state.

Effect of algae or fish oil supplementation and porcine maternal stress on the adrenal transcriptome of male offspring fed a low-quality protein diet

Offspring adrenal function may be negatively affected in utero by maternal stressors such as microbial infection. Maternal supplementation with immunomodulatory compounds such as omega-3 polyunsaturated fatty acids (n-3 PUFA) may help minimize the adverse effects of maternal stress on fetal hypothalamic-pituitary-adrenal development and improve offspring health. Presently, n-3 PUFA sources are primarily fish-based, but n-3 PUFA microalgae (AL) may be an alternative. Previously, it was determined that maternal AL or fish oil (FO) supplementation to sows, in addition to maternal stress induced by Escherichia coli lipopolysaccharide (LPS) challenge appeared to have a greater influence on the stress response of male offspring compared to females. To further elaborate on these findings, this study assessed the effects of maternal AL or FO supplementation combined with a maternal LPS challenge on adrenal gene expression in male offspring fed a nursery diet containing low-quality protein sources. Forty-eight sows were fed gestation diets starting on gestation day (gd) 75 containing either 3.12% AL, 3.1% FO, or a control diet containing 1.89% corn oil. On gd 112, half the sows in each treatment were administered 10 ​μg/kg LPS i.m. Piglets were weaned at 21 days of age onto a common low-quality plant-based protein diet, and one week after weaning, four piglets per sow were administered 40 ​μg/kg LPS i.m. Two hours later, the piglets were euthanized to obtain adrenal tissue, and total RNA was extracted to carry out transcriptome analysis using the Affymetrix GeneChip WT Plus assay and subsequent validation by real-time PCR. Analysis revealed that adrenal steroidogenesis, fatty acid metabolism and immune function were significantly influenced by maternal diet and stress. Increased expression of immune-related genes including lymphocyte antigen 96, TLR-2 and NF-κB suggests that maternal AL supplementation may increase offspring sensitivity to inflammation after weaning. Decreased expression of lymphocyte antigen 96 in male offspring from sows receiving maternal LPS challenge also suggests a possible role of maternal stress in diminishing the offspring immune response to immune stress challenge. Increased expression of the genes encoding the 11BHSD2 enzyme in offspring from sows fed FO may also reduce the magnitude of the stress response. These data provide insight to the immune and metabolic mechanisms that may be influenced by maternal diet and stress.

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Expression of adrenal steroidogenesis genes were influenced by maternal treatment.

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Expression of lipid metabolism genes and immune function genes were enriched.

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Maternal algae supplementation may increase offspring sensitivity to inflammation.

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Maternal stress may reduce the offspring immune response to immune challenges.

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Maternal fish oil supplementation may reduce the offspring stress response.

Role of corticosterone on sleep homeostasis induced by REM sleep deprivation in rats

Sleep is regulated by humoral and homeostatic processes. If on one hand chronic elevation of stress hormones impair sleep, on the other hand, rapid eye movement (REM) sleep deprivation induces elevation of glucocorticoids and time of REM sleep during the recovery period. In the present study we sought to examine whether manipulations of corticosterone levels during REM sleep deprivation would alter the subsequent sleep rebound. Adult male Wistar rats were fit with electrodes for sleep monitoring and submitted to four days of REM sleep deprivation under repeated corticosterone or metyrapone (an inhibitor of corticosterone synthesis) administration. Sleep parameters were continuously recorded throughout the sleep deprivation period and during 3 days of sleep recovery. Plasma levels of adrenocorticotropic hormone and corticosterone were also evaluated. Metyrapone treatment prevented the elevation of corticosterone plasma levels induced by REM sleep deprivation, whereas corticosterone administration to REM sleep-deprived rats resulted in lower corticosterone levels than in non-sleep deprived rats. Nonetheless, both corticosterone and metyrapone administration led to several alterations on sleep homeostasis, including reductions in the amount of non-REM and REM sleep during the recovery period, although corticosterone increased delta activity (1.0-4.0 Hz) during REM sleep deprivation. Metyrapone treatment of REM sleep-deprived rats reduced the number of REM sleep episodes. In conclusion, reduction of corticosterone levels during REM sleep deprivation resulted in impairment of sleep rebound, suggesting that physiological elevation of corticosterone levels resulting from REM sleep deprivation is necessary for plentiful recovery of sleep after this stressful event.

Increases in systemic and local stress: a probable mechanism of visceral fat accumulation and insulin resistance in adult catch-up growth rats?

Catch-up growth in adult (CUGA) is increasingly proposed as an important causative factor for the widespread insulin resistance (IR)-related diseases especially in developing countries/territories. We aimed to investigate the effects of CUGA to insulin sensitivity, lipid profile and stress in rats, as well as the probable relationship among them. Male Sprague-Dawley rats were randomly divided into six groups for two sampling points: caloric restriction group (R4) and normal chow controls for four weeks (NC4); CUGA re-fed with normal chow (RN4), CUGA re-fed with high-fat diet (RH4), normal chow controls (NC8) and high-fat diet controls (HF8) for eight weeks. Visceral fat accumulation (visceral adipose tissue [VAT] percentage), systemic (plasma corticosterone) and local (HSD11B1 mRNA expression in skeletal muscle [SkM] and VAT) stress, whole-body and peripheral insulin sensitivity were determined in this study. After four weeks of caloric restriction, R4 rats showed increases in systemic and local stress, decreases in visceral fat accumulation and no IR (whole-body or peripheral). Yet, after re-feeding, sustained systemic and local stress, remarkable visceral fat accumulation and IR (whole-body and peripheral) were found in RN4 compared with NC8, in RH4 compared with NC8 and HF8. Our findings demonstrated that CUGA rats were characterized by significant IR, visceral fat accumulation and stress. These changes were more severe in CUGA re-fed with high-fat diet. The interaction of sustained caloric restriction-induced stress and re-feeding might be of utmost importance in the etiology of visceral fat accumulation and IR in CUGA.

Effects of menopause on hepatic 11β-hydroxysteroid dehydrogenase type 1 activity and adrenal sensitivity to adrenocorticotropin in healthy non-obese women

Menopause is associated with central obesity, dyslipidemia, hypertension and insulin resistance, which are also shown in the patients with excess of glucocorticoids. However, the interaction of hypothalamic-pituitary-adrenal (HPA) axis activity and menopause has not been fully understood. In this study, 55 healthy non-obese women were recruited, and then divided into two groups, premenopausal group (n = 24) and postmenopausal group (n = 31). HPA axis function was evaluated by using dexamethasone suppression test (DST; 0.25 mg), and adrenocorticotrophic hormone (ACTH)-stimulation test. Moreover, 25 mg cortisone acetate test was applied to evaluate the hepatic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity. We found that hepatic 11β-HSD1 activity and adrenal response to ACTH were increased in the postmenopausal group compared with the premenopausal group, whereas the negative feedback effect of dexamethasone did not show significant difference between pre- and postmenopausal women. These findings suggest that the adrenal sensitivity to ACTH and hepatic 11β-HSD1 activity are increased. The increased cortisol conversion and/or synthesis may be contributed to the dysmetabolic features in the postmenopausal women.

Hepatic 11 beta-hydroxysteroid dehydrogenase 1 involvement in alterations of glucose metabolism produced by acidotic stress in rat

11 beta-hydroxysteroid dehydrogenase (HSDs) enzymes regulate the activity of glucocorticoids in target organs. HSD1, one of the two existing isoforms, locates mainly in CNS, liver and adipose tissue. HSD1 is involved in the pathogenesis of diseases such as obesity, insulin resistance, arterial hypertension and the Metabolic Syndrome. The stress produced by HCl overload triggers metabolic acidosis and increases liver HSD1 activity associated with increased phosphoenolpyruvate carboxykinase, a regulatory enzyme of gluconeogenesis that is activated by glucocorticoids, with increased glycaemia and glycogen breakdown. The aim of this study was to analyze whether the metabolic modifications triggered by HCl stress are due to increased liver HSD1 activity. Glycyrrhetinic acid, a potent HDS inhibitor, was administered subcutaneously (20 mg/ml) to stressed and unstressed four months old maleSprague Dawley rats to investigate changes in liver HSD1, phosphoenolpyruvate carboxykinase (PECPK) and glycogen phosphorylase activities and plasma glucose levels. It was observed that all these parameters increased in stressed animals, but that treatment with glycyrrhetinic acid significantly reduced their levels. In conclusion, our results demonstrate the involvement of HSD1 in stress induced carbohydrate disturbances and could contribute to the impact of HSD1 inhibitors on carbohydrate metabolism and its relevance in the study of Metabolic Syndrome Disorder and non insulin-dependent diabetes mellitus.

Effect of stress on hepatic 11beta-hydroxysteroid dehydrogenase activity and its influence on carbohydrate metabolism

Stress activates the synthesis and secretion of catecholamines and adrenal glucocorticoids, increasing their circulating levels. In vivo, hepatic 11beta-hydroxysteroid dehydrogenase 1 (HSD1) stimulates the shift of 11-dehydrocorticosterone to corticosterone, enhancing active glucocorticoids at tissue level. We studied the effect of 3 types of stress, 1 induced by bucogastric overload with 200 mmol/L HCl causing metabolic acidosis (HCl), the second induced by bucogastric overload with 0.45% NaCl (NaCl), and the third induced by simulated overload (cannula), on the kinetics of hepatic HSD1 of rats and their influence on the activity of the gluconeogenic enzyme phosphoenolpyruvate carboxykinase, glycemia, and glycogen deposition. Compared with unstressed controls, all types of stress significantly increased HSD1 activity (146% cannula, 130% NaCl, and 253% HCl), phosphoenolpyruvate carboxykinase activity (51% cannula, 48% NaCl, and 86% HCl), and glycemia (29% cannula, 30% NaCl, and 41% HCl), but decreased hepatic glycogen (68% cannula, 68% NaCl, and 78% HCl). Owing to these results, we suggest the following events occur when stress is induced: an increase in hepatic HSD1 activity, augmented active glucocorticoid levels, increased gluconeogenesis, and glycemia. Also involved are the multiple events indirectly related to glucocorticoids, which lead to the depletion of hepatic glycogen deposits, thereby contributing to increased glycemia. This new approach shows that stress increments the activity of hepatic HSD1 and suggests that this enzyme could be involved in the development of the Metabolic Syndrome.