Plasma Corticosterone Levels In Mice Research Articles

367-OR: E-cigarette Vaping Exposure Increases Adipose 11ß-HSD1 Expression and Disturbs Glucose Homeostasis in Mice

Electronic cigarette (E-cigs) use may increase the prediabetic risk, but the underlying mechanisms remain underexplored. Pre-receptor activation of glucocorticoids (GCs) via 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in adipose tissues has been identified as an important mediator of insulin resistance and type 2 diabetes. However, little is known about the effects of E-cig vaping on 11β-HSD1 and glucose homeostasis. To address this issue, we conducted animal model studies with mice exposed to aerosolized PBS, nicotine-free or nicotine-containing E-cigs, with concurrent exposure to either vehicle or the GC receptor (GR) antagonist RU486. We observed that exposure of E-cig vaping nicotine for 4 weeks increased 11β-HSD1 expression and induced lipase HSL and ATGL abundance within the adipose tissues with induction of hypercortisolemia in response to elevated plasma nicotine levels in mice compared with those of aerosolized E-cig vaping vehicle or PBS controls. Induction of adipose 11β-HSD1 was correlated with elevated the expression of hepatic gluconeogenic enzymes PEPCK and G6Pase and corresponded to the elevated fasting glucose levels. Moreover, E-cig vaping nicotine also increased glucose intolerance, but decreased the glucose-lowing effects of insulin and elevated plasma FFA levels in mice compared with PBS controls. However, E-cig vapor without nicotine did not affect these metabolic parameters. Furthermore, RU486 treatment attenuated E-cig vaping nicotine-induced adipose 11β-HSD1 and lipase expression. In addition, RU486 also attenuated the E-cig-mediated activation of hepatic PEPCK and G6Pase and decreased plasma FFA levels, but did not change the elevated plasma corticosterone levels in mice on E-cig vaping nicotine. These data indicate that E-cig vapor exposure harmfully affects glucose homeostasis and these effects may arise, in part, from aerosol nicotine-induced adipose 11β-HSD1 and GR expression. Disclosure J.Wang: None. T.Friedman: None. M.Jiang: None. Y.Liu: None. J.Liu: None. Y.Wang: None. S.C.J.Kim: None. E.Espinal: None. R.Yang: None. H.Zhong: None. X.M.Shao: None. K.Lutfy: None. Funding Tobacco-Related Disease Research Program (T31IR1603)

Effects of CRN04894, a Nonpeptide Orally Bioavailable ACTH Antagonist, on Corticosterone in Rodent Models of ACTH Excess

CRN04894 is an orally administered nonpeptide that is a potent and selective antagonist for adrenocorticotropic hormone (ACTH) acting at the melanocortin 2 receptor (MC2R) and is currently under development for the treatment of diseases of ACTH excess such as Cushing’s disease, congenital adrenal hyperplasia, and ectopic ACTH-secreting tumors. Cushing’s disease results from an adenoma derived from pituitary corticotropic cells that secrete excess ACTH, whereas ectopic ACTH syndrome arises from nonpituitary ACTH secreting tumors. Congenital adrenal hyperplasia is a genetic disease that results in cortisol deficiency leading to high levels of ACTH and adrenal androgens. Each of these indications is characterized by high ACTH levels that act on MC2R expressed in the adrenal cortex to drive pathological elevations of adrenally derived steroid hormones. CRN04894 blocks the action of ACTH at MC2R, providing a potential novel treatment for these diseases. Preclinical models of chronic hypercortisolemia include implantation of ACTH-secreting pituitary tumor cells in mice and continuous administration of ACTH via subcutaneously implanted osmotic pumps in rats. These models induce features consistent with human diseases of ACTH excess including hypercortisolemia and hypertrophy of the adrenal glands. We employed both rodent models to examine the pharmacodynamic effects of CRN04894 on corticosterone levels and adrenal gland morphology. In the mouse pituitary tumor model, subcutaneous inoculation of the ACTH-secreting mouse pituitary tumor cell line, AtT-20, into immunodeficient mice resulted in formation of tumors and increased plasma ACTH and corticosterone levels. Repeated daily oral administration of CRN04894 for 14 days dose-dependently and robustly suppressed plasma corticosterone levels in mice with AtT-20 tumors. In the rat model, subcutaneous implantation of osmotic pumps delivering ACTH resulted in increased corticosterone levels, reduction in body weight, and hypertrophy of the adrenal glands after 7 days. Daily oral administration of CRN04894 over 7 days dose-dependently suppressed corticosterone levels, mitigated the effect of ACTH excess on body weight, and rescued the adrenal gland hypertrophy. These findings provide evidence that CRN04894 functions as an effective ACTH antagonist at MC2R to suppress adrenal corticosterone secretion in both mouse and rat models of ACTH excess and hypercortisolemia, thus providing a strong rationale for its potential therapeutic utility in diseases of ACTH excess. This work was supported in part by an SBIR grant from the NIH awarded to Dr. Struthers (R43- DK115245)

Gum Arabic Modifies Glucocorticoid Metabolic Enzymes Gene Associated with Decreased Plasma Corticosterone Levels in Mice

Glucocorticoids (GCs), corticosterone in rodents and cortisol in humans are endogenous stress hormones that exert key...

Shi Xiao San ameliorates the development of adenomyosis in an ICR mouse model

The use of Shi Xiao San (SXS), composed of Pollen Typhae Angustifoliae and Faeces Trogopterori, can be traced back to the Song dynasty. Traditionally, SXS has been used to treat irregular menstruation, pelvic pain, progressive dysmenorrhea, and postpartum lochiorrhea. The management of adenomyosis (AM) is challenging and to the best of our knowledge there are currently no effective therapeutic strategies. Therefore, the aim of the present study was to investigate the effect of SXS on the development of adenomyosis in a mouse model. AM was induced in 60 neonatal female ICR mice by administering tamoxifen; 10 randomly selected mice were used for model identification via histopathological examination and 10 mice treated with the solvent alone were used as the normal controls. A total of sixty days after birth, the mice treated with AM were randomly divided into four groups and administered one of the following treatments: Low-dose SXS (55 mg/kg); high-dose SXS (110 mg/kg); danazol (1 mg/20 g body weight); or no treatment (model group); at the same time, the normal control group received no treatment. After 2 months of treatment, hotplate and tail-flick tests were used to assess the response to noxious thermal stimuli in the mice, and plasma samples were collected to measure corticosterone levels. Hematoxylin and eosin staining scores of myometrial infiltration and the number of AM nodules were evaluated. Furthermore, the expression of genes associated with AM-related pain was also analyzed. The results from the present study indicated that treatment with SXS decreased myometrial infiltration, alleviated generalized hyperalgesia, and lowered plasma corticosterone levels in mice with induced AM. These findings suggest that SXS effectively attenuated the development of AM, and may serve as a promising treatment approach for AM treatment.

Activation of amylin receptors attenuates alcohol-mediated behaviours in rodents.

Alcohol expresses its reinforcing properties by activating areas of the mesolimbic dopamine system, which consists of dopaminergic neurons projecting from the ventral tegmental area to the nucleus accumbens. The findings that reward induced by food and addictive drugs involve common mechanisms raise the possibility that gut–brain hormones, which control appetite, such as amylin, could be involved in reward regulation. Amylin decreases food intake, and despite its implication in the regulation of natural rewards, tenuous evidence support amylinergic mediation of artificial rewards, such as alcohol. Therefore, the present experiments were designed to investigate the effect of salmon calcitonin (sCT), an amylin receptor agonist and analogue of endogenous amylin, on various alcohol‐related behaviours in rodents. We showed that acute sCT administration attenuated the established effects of alcohol on the mesolimbic dopamine system, particularly alcohol‐induced locomotor stimulation and accumbal dopamine release. Using the conditioned place preference model, we demonstrated that repeated sCT administration prevented the expression of alcohol's rewarding properties and that acute sCT administration blocked the reward‐dependent memory consolidation. In addition, sCT pre‐treatment attenuated alcohol intake in low alcohol‐consuming rats, with a more evident decrease in high alcohol consumers in the intermittent alcohol access model. Lastly, sCT did not alter peanut butter intake, blood alcohol concentration and plasma corticosterone levels in mice. Taken together, the present data support that amylin signalling is involved in the expression of alcohol reinforcement and that amylin receptor agonists could be considered for the treatment of alcohol use disorder in humans.

Corticosterone does not change open elevated plus maze-induced antinociception in mice

It has been demonstrated that the exposure of rodents to the standard elevated plus-maze (sEPM: 2 open and 2 enclosed arms) elicits defensive behavioral reactions and antinociception and also activates the hypothalamo-pituitary-adrenal (HPA) axis. We have recently reported that EPM-induced antinociception is particularly observed when rats and mice are exposed to a totally open EPM (oEPM: 4 open arms). Given that the oEPM seems to be a more aversive situation than the sEPM, we hypothesized that oEPM exposure would induce higher plasma levels of corticosterone than sEPM exposure in mice. In this study, we investigated the influence of exposure to eEPM (enclosed EPM: 4 enclosed arms), sEPM or oEPM on plasma corticosterone levels in mice, with or without prior nociceptive stimulation (2.5% formalin injection into the right hind paw). We also tested whether the nociceptive response in the formalin test and oEPM-induced antinociception are altered by adrenalectomy. Results showed that oEPM-exposed mice spent less time licking the injected paw than sEPM- and eEPM-exposed animals. All three types of EPM exposure increased plasma corticosterone when compared to the basal group, but sEPM- and oEPM-exposed mice showed higher corticosterone levels than eEPM-exposed mice. Prior nociceptive stimulation (formalin injection) did not enhance the plasma corticosterone response induced by the three types of EPM exposure. Indeed, formalin injection appeared to provoke a ceiling effect on plasma corticosterone concentration. Furthermore, neither the nociceptive response in the formalin test nor oEPM-induced antinociception was changed by adrenalectomy. Present results suggest that oEPM antinociception does not depend on corticosterone release in mice.

Safety of glucocorticoids can be improved by lower yet still effective dosages of liposomal steroid formulations in murine antigen-induced arthritis: Comparison of prednisolone with budesonide

The goal of this study was to compare the effects of liposomal and free glucocorticoid formulations on joint inflammation and activity of the hypothalamic-pituitary-adrenal (HPA) axis during experimental antigen-induced arthritis (AIA). A dose of 10 mg/kg liposomal prednisolone phosphate (PLP) gave a suppression of the HPA-axis, as measured by plasma corticosterone levels in mice with AIA and in naïve mice. In a subsequent dose-response study, we found that a single dose of 1 mg/kg liposomal prednisolone phosphate (PLP) was still equally effective in suppressing joint inflammation as 4 repeated once-daily injections of 10 mg/kg free PLP. Moreover, the 1 mg/kg liposomal PLP dose gave 22% less suppression of corticosterone levels than 10 mg/kg of liposomal PLP at day 14 of the AIA. In order to further optimize liposomal glucocorticoids, we compared liposomal PLP with liposomal budesonide phosphate (BUP) (1 mg/kg). At 1 day after treatment, liposomal BUP gave a significantly stronger suppression of joint swelling than liposomal PLP (lip. BUP 98% vs. lip. PLP 79%). Both formulations also gave a strong and lasting suppression of synovial infiltration in equal amounts. However, at day 21 after AIA, liposomal PLP still significantly suppressed corticosterone levels, whereas this suppression was not longer statistically significant for liposomal BUP. Conclusion: Liposomal delivery improves the safety of glucocorticoids by allowing for lower effective dosing. The safety of liposomal glucocorticoid may be further improved by encapsulating BUP rather than PLP.

Effects of sex, age and sampling method on plasma corticosterone levels in mice

Effects of sex, age and sampling method on plasma corticosterone levels in mice

Acute restraint stress enhances calcium mobilization and proliferative response in splenic lymphocytes from mice

Calcium (Ca2+ ) plays an essential role in lymphocyte activation and maturation. Acute and chronic stress has been shown to modulate the lymphocyte immune response; but the relationship between cytosolic free Ca2+ concentration ([Ca2+ ]i) and the immune response in lymphocytes following exposure to stress has not been examined. In the present study, we investigated the effects of acute restraint stress on [Ca2+ ]i and the proliferation of splenic lymphocytes from mice. We observed that 2 h of restraint significantly increased plasma corticosterone levels in mice. On examining [Ca2+ ]i and the proliferation ex vivo of splenic lymphocytes isolated from restraint-stressed mice using fura-2 and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide, respectively, we found that acute restraint stress caused a significant increase in resting [Ca2+ ]i and significantly enhanced the ability of concanavalin A (Con A; a T-cell-selective mitogen) to increase [Ca2+ ]i but not that of lipopolysaccharide (LPS; a B-cell-selective mitogen). In addition, acute restraint stress significantly enhanced Con A-stimulated but not LPS-stimulated lymphocyte proliferation. Overall, there was a positive correlation between [Ca2+ ]i and T-cell proliferation following acute restraint stress. The enhancements of [Ca2+ ]i and T-cell proliferation were completely suppressed by verapamil (a Ca2+ channel blocker). These results suggest that acute restraint stress enhances Con A-stimulated T-cell proliferation by increasing [Ca2+ ]i via stimulation of Ca2+ entry.

Route-dependent effects of the non-NMDA receptor antagonist CNQX on plasma corticosterone levels in mice

A non- N-methyl- d-aspartate (non-NMDA) receptor antagonist, 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX), administered intracerebroventricularly (0.1–0.5 μg), significantly inhibited the immobilization stress-induced plasma corticosterone levels in a dose-dependent manner. However, CNQX administered intraperitoneally (1–10 mg/kg) showed a dose-dependent increase of basal plasma corticosterone levels in nonstressed mice and an additive increase of plasma corticosterone levels at the dose of 10 mg/kg in 1 h immobilization-stressed mice. The results suggest that the central and peripheral non-NMDA receptors may be differently involved in the regulation of plasma corticosterone levels in non- and immobilization-stressed mice.

Effects of ginseng saponin administered intraperitoneally on the hypothalamo-pituitary-adrenal axis in mice

Intraperitoneal injection of ginseng total saponin (GTS; 5 and 20 mg/kg) raised plasma corticosterone levels in mice. However, interestingly, pretreatment of animals with the same doses of GTS (5 and 20 mg/kg) significantly attenuated the immobilization stress-induced increase in plasma corticosterone levels. Of the ginsenosides Rb 1, Rb 2, Rc, Rd, Re, Rf, Rg 1, 20(S)-Rg 3, and 20(R)-Rg 3 injected intraperitoneally at doses of 0.1–2 mg/kg, Rc (2 mg/kg) significantly inhibited the immobilization stress-induced increase in plasma corticosterone levels. GTS and Rc administered intraperitoneally did not affect the immobilization stress-induced elevation of plasma adrenocorticotropic hormone (ACTH) level. Pretreatment with GTS and Rc significantly attenuated the increase in plasma corticosterone levels induced by intraperitoneal injection of ACTH (30 μg/kg). These results suggest that GTS and Rc inhibit the immobilization stress-induced increase in plasma corticosterone levels by blocking ACTH action in the adrenal gland. Ginseng may be proposed to be useful for treatment of stress related disorders.

Inhibition of brain protein kinase C attenuates immobilization stress-induced plasma corticosterone levels in mice

To evaluate the involvement of brain protein kinase C (PKC) in the stress-induced activation of hypothalamic-pituitary-adrenal (HPA) axis, we examined the effects of PKC inhibitors administered intracerebroventricularly (i.c.v.) on the immobilization stress-induced plasma corticosterone levels in mice. Calphostin C (a pan-specific PKC inhibitor) injected i.c.v. decreased the immobilization stress-induced plasma corticosterone level: maximal inhibition of 35% was attained at a dose of 100 pmol. Gö 6976 (an α and β1 PKC isotype-selective inhibitor) was less effective than Calphostin C: maximal inhibition of 17% was attained at a dose of 30 pmol. Phorbol 12-myristate 13-acetate (a general PKC activator) injected i.c.v. at doses of 16 and 48 pmol increased the plasma corticosterone levels in a dose-dependent manner. The present study demonstrates the involvement of PKC in the brain in the regulation of the immobilization stress-induced stimulation of HPA axis in vivo.

Inhibition of stress-induced plasma corticosterone levels by ginsenosides in mice: involvement of nitric oxide.

Ginseng total saponins (GTS) injected intracerebroventricularly (i.c.v.) at doses of 0.1-1 microg inhibited the i.c.v. injection stress-induced plasma corticosterone levels in mice. The inhibitory action of GTS was blocked by co-administered N(G)-nitro-L-arginine methyl ester (L-NAME; 1.5 microg, i.c.v.), an inhibitor of nitric oxide synthase (NOS). Of the ginsenosides Rb1, Rb2, Rc, Rd, Re, Rf, Rg1, 20(S)-Rg3 and 20(R)-Rg3 injected i.c.v. at doses of 0.01-1 microg, 20(S)-Rg3 and Rc significantly inhibited the i.c.v. injection stress-induced plasma corticosterone levels. The inhibitory actions of 20(S)-Rg3 and Rc were blocked by co-administered L-NAME (1.5 microg, i.c.v.). These results suggest that GTS, 20(S)-Rg3 and Rc may inhibit the i.c.v. injection stress-induced hypothalamo-pituitary-adrenal response by inducing NO production in the brain.

Intracerebroventricular injection-induced increase in plasma corticosterone levels in the mouse: a stress model

The method of intracerebroventricular (i.c.v.) injection of drugs to conscious mice is a simple and useful technique for studying the central actions of drugs in mice. However, the use of this technique to dissect the central regulatory mechanisms of stress-activated hypothalamo-pituitary-adrenocortical (HPA) axis may produce confusing results difficult to interpret, because i.c.v. injection itself induces an increase in plasma corticosterone in mice due to the traumatic nature of the technique. Here we propose to use the i.c.v. injection itself as a stress stimulus in mice. An i.c.v. saline injection induced an increase in plasma corticosterone levels in mice, which reached a maximum of 38.0 ± 1.9 μg/100 ml at 30 min after the i.c.v. injection. α-Helical corticotropin-releasing factor (CRF) 9-41, a CRF antagonist, injected i.c.v. (1, 3 μg), effectively inhibited the injection stress-induced rise in plasma corticosterone levels, suggesting the involvement of CRF in this response. This i.c.v. injection stress model permits the evaluation of the effects of drugs administered i.c.v. simultaneously.

Disturbed immuno-endocrine communication via the hypothalamo-pituitary-adrenal axis in autoimmune disease.

Previous studies in our laboratory demonstrated an altered immuno-endocrine feedback communication via the hypothalamo-pituitary-adrenal (HPA) axis, which may be an important modulatory factor in the development of spontaneous autoimmune thyroiditis in Obese strain (OS) chickens. These birds show a significantly lower, or even absent, increase in serum glucocorticoid levels in response to an intravenous injection of antigen or conditioned medium (CM) from mitogen-stimulated spleen cells known to contain glucocorticoid-increasing factors (GIFs), notably interleukin-1 (IL-1). The present study was aimed at investigating this feedback regulation in animal models with spontaneous systemic autoimmune diseases, such as the UCD-200 chicken, which serves as a model for human scleroderma, and various murine lupus models. In contrast to OS chickens, UCD-200 chickens displayed a nearly normal plasma corticosterone surge in response to CM, and IL-1 was again identified as the primary GIF in CM. Recombinant IL-1 also induced a drastic increase in plasma corticosterone levels in various strains of normal mice. A similar increase was observed in the bacterial lipopolysaccharide-resistant C3H/HeJ strain, thus excluding the possibility of bacterial endotoxin contamination. However, in young lupus-prone (NZB/W)F1 and MRL/MP-lpr mice, a significantly lower increase in plasma corticosterone levels was observed after injection of recombinant IL-1, suggesting a deficient immuno-endocrine communication via the HPA loop in this instance as well. Detailed studies to identify further cytokines with GIF activity in the avian and murine systems showed that both IL-6 and tumor necrosis factor-alpha could induce increased plasma corticosterone levels in mice, but not in chickens. IL-3, IL-8, transforming growth factor-beta, interferon-gamma and granulocyte-macrophage colony-stimulating factor were devoid of GIF activity in both chickens and mice.

The effects of selective opioid delta-receptor antagonists on stress-induced antinociception and plasma corticosterone levels in mice

Antinociception produced in mice by a 3 min swim was attenuated by ICI 174,864 and by low doses of naloxone indicating the involvement of both δ- and μ-receptors. The degree of antinociception was not related to plasma corticosterone (CS) levels measured 11 min after the swim. Naloxone affected CS levels in control mice and appeared to reduce the CS response to stress: ICI 154,129 and ICI 174,864 did not produce consistent effects on plasma CS levels.

The effect of intracerebroventricular administration of methionine-enkephalin on the stress-induced secretion of corticosterone in mice.

Ether stress or intracerebroventricular (i.c.v.) administration of saline, met-enkephalin, or naltrexone raised plasma corticosterone levels in mice. The response to ether stress was abolished by a preceding ether stress or by pretreatment with i.c.v. saline or naltrexone. However, following i.c.v. met-enkephalin, plasma corticosterone was significantly elevated by ether stress, the effect being blocked by simultaneous injection of met-enkephalin and naltrexone. Met-enkephalin appears to prevent fast-feedback inhibition of the hypothalamus-pituitary-adrenal system.

The relation between social rank and plasma corticosterone levels in mice

Male CFW mice that had been isolated since weaning were placed in groups of four for six hours and 24 hours and observed for the development of aggressive behavior patterns and dominance hierarchies. Control animals were maintained in individual cages. At the end of the grouping period the animals were sacrificed by decapitation and plasma corticosterone levels and adrenal weight recorded. There was a distinct relation between position in a dominance hierarchy and plasma corticosterone levels with dominant animals having significantly lower levels than subordinate ones. Thus these data corroborate the findings of earlier workers who used indirect criteria for adrenocortical activity. The results further support the hypothesis that the psychological factor of defeat after fighting is important in eliciting adrenocortical activity. Thus subordinate mice were frequently defeated and chased resulting in a high frequency of wounding on the tail and rump. Dominant animals, on the other hand, were not frequently defeated and showed very few injuries to the tail and rump.