scholarly journals Serotonin depletion does not alter lipopolysaccharide-induced activation of the rat paraventricular nucleus

1998 ◽  
Vol 156 (2) ◽  
pp. 245-251 ◽  
Author(s):  
GL Conde ◽  
D Renshaw ◽  
SL Lightman ◽  
MS Harbuz
Keyword(s):  
Hpa Axis ◽  
Paraventricular Nucleus ◽  
Plasma Corticosterone ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Experimental Conditions ◽  
Serotonin Depletion ◽  
Corticotrophin Releasing Factor ◽  
Subsequent Activation ◽  
High Doses

We have investigated the effects of serotonin depletion on immune-mediated activation of the hypothalamo-pituitary-adrenal (HPA) axis. Corticotrophin-releasing factor (CRF) mRNA, c-fos mRNA and Fos peptide responses in the paraventricular nucleus (PVN) together with circulating levels of corticosterone were assessed in response to i.p. injections of three doses of lipopolysaccharide (LPS) both in control animals and animals pretreated with p-chlorophenylalanine (PCPA). Conscious animals received either an i.p. injection of 0.5 ml saline or 200 mg/kg PCPA in 0.5 ml saline on 2 consecutive days. This treatment resulted in a 93% depletion of serotonin on the fourth day. On day 4, animals received i.p. injections of LPS (2.5 mg/0.5 ml saline, 250 micrograms/0.5 ml or 50 micrograms/0.5 ml; E. coli 055:B5), or saline injections as controls. Pretreatment with PCPA had no effect on the basal levels of corticosterone, or on the elevated levels induced by the three doses, of LPS. Fos peptide and c-fos mRNA were undetectable in control animals, and Fos-like immunoreactivity increased in a dose-dependent manner following i.p. LPS in both control and PCPA-pretreated animals. C-fos mRNA expression induced by LPS was unaffected by serotonin depletion. Following the lowest dose of LPS, CRF mRNA did not change above control levels, however, the medium and high doses of LPS produced a significant (P < 0.05) increase in CRF mRNA levels in both depleted and intact animals. To confirm the temporal effects of serotonin depletion on activation of the HPA axis we collected plasma at 30 min, 1, 2, 3, 4, 5, and 6 h after LPS in both intact and serotonin-depleted animals. No significant differences in plasma corticosterone levels were found at any of the time points between intact and depleted animals. It appears that, at least under these experimental conditions, serotonergic inputs do not seem to play a major role in mediating the effects of LPS on changes in mRNA levels in the PVN or on the subsequent activation of the HPA axis.

scholarly journals A Novel Mouse Model for Acute and Long-Lasting Consequences of Early Life Stress

Endocrinology ◽  
2008 ◽  
Vol 149 (10) ◽  
pp. 4892-4900 ◽  
Author(s):  
Courtney J. Rice ◽  
Curt A. Sandman ◽  
Mohammed R. Lenjavi ◽  
Tallie Z. Baram
Keyword(s):  
Mouse Model ◽  
Paraventricular Nucleus ◽  
Life Stress ◽  
Early Life ◽  
Molecular Mechanisms ◽  
Early Life Stress ◽  
Plasma Corticosterone ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Basal Plasma

Chronic early-life stress (ES) exerts profound acute and long-lasting effects on the hypothalamic-pituitary-adrenal system, with relevance to cognitive function and affective disorders. Our ability to determine the molecular mechanisms underlying these effects should benefit greatly from appropriate mouse models because these would enable use of powerful transgenic methods. Therefore, we have characterized a mouse model of chronic ES, which was provoked in mouse pups by abnormal, fragmented interactions with the dam. Dam-pup interaction was disrupted by limiting the nesting and bedding material in the cages, a manipulation that affected this parameter in a dose-dependent manner. At the end of their week-long rearing in the limited-nesting cages, mouse pups were stressed, as apparent from elevated basal plasma corticosterone levels. In addition, steady-state mRNA levels of CRH in the hypothalamic paraventricular nucleus of ES-experiencing pups were reduced, without significant change in mRNA levels of arginine vasopressin. Rearing mouse pups in this stress-provoking cage environment resulted in enduring effects: basal plasma corticosterone levels were still increased, and CRH mRNA levels in paraventricular nucleus remained reduced in adult ES mice, compared with those of controls. In addition, hippocampus-dependent learning and memory functions were impaired in 4- to 8-month-old ES mice. In summary, this novel, robust model of chronic early life stress in the mouse results in acute and enduring neuroendocrine and cognitive abnormalities. This model should facilitate the examination of the specific genes and molecules involved in the generation of this stress as well as in its consequences.

Lipopolysaccharide is able to bypass corticotrophin-releasing factor in affecting plasma ACTH and corticosterone levels: evidence from rats with lesions of the paraventricular nucleus

1992 ◽  
Vol 133 (2) ◽  
pp. 231-236 ◽  
Author(s):  
I. J. Elenkov ◽  
K. Kovács ◽  
J. Kiss ◽  
L. Bertók ◽  
E. S. Vizi
Keyword(s):  
Hpa Axis ◽  
Paraventricular Nucleus ◽  
Physiological Responses ◽  
Plasma Acth ◽  
Experimental Conditions ◽  
Corticotrophin Releasing Factor ◽  
Adrenal System ◽  
Lps Treatment ◽  
Stimulation Of

ABSTRACT Stimulation of the immune system or experimental conditions (bacterial lipopolysaccharide (LPS) treatment) provoke a broad spectrum of physiological responses. It was recently shown that one of them is the activation of the hypothalamic-pituitary-adrenal (HPA) axis. The mechanism and the site or sites through which LPS stimulates the HPA axis are not well understood. To establish whether the effect of bacterial LPS is related in vivo to the presence of hypothalamic hypophysiotrophic peptides (corticotrophin-releasing factor-41, arginine vasopressin, etc.), plasma ACTH and corticosterone levels were monitored in intact and sham-operated rats, and in rats with paraventricular nucleus lesions in order to remove the main source of these neuropeptides. Evidence was obtained that 4 h after treatment, LPS was able to activate the hypophysial-adrenal system in the absence of hypophysiotrophic neuropeptides of paraventricular origin. It is suggested that, in vivo, LPS could have a direct effect on the pituitary gland or that it acts through an extrapituitary, non-paraventricular pathway to activate the HPA axis. Journal of Endocrinology (1992) 133, 231–236

Neonatal monosodium glutamate treatment alters both the activity and the sensitivity of the rat hypothalamo-pituitary-adrenocortical axis

1994 ◽  
Vol 141 (3) ◽  
pp. 497-503 ◽  
Author(s):  
P J Larsen ◽  
J D Mikkelsen ◽  
D Jessop ◽  
S L Lightman ◽  
H S Chowdrey
Keyword(s):  
Hpa Axis ◽  
Restraint Stress ◽  
Acute Stress ◽  
Monosodium Glutamate ◽  
Plasma Corticosterone ◽  
Mrna Levels ◽  
Plasma Acth ◽  
Corticotrophin Releasing Factor ◽  
Acute And Chronic Stress ◽  
Corticosterone Response

Abstract We have investigated the effects of monosodium glutamate (MSG) lesioning of the arcuate nucleus on both central and peripheral components of the hypothalamo-pituitary-adrenocortical (HPA) axis under basal conditions and under acute and chronic stress. Plasma ACTH levels were lower in MSG-lesioned rats (27 ± 7 pg/ml) compared with controls (71 ± 18 pg/ml) while corticosterone levels were elevated (523 ± 84 ng/ml compared with 176 ± 34 ng/ml). Quantititative in situ hybridization histochemistry revealed that corticotrophin-releasing factor mRNA levels in the medial parvocellular part of the hypothalamic paraventricular nucleus were significantly lower in MSG-treated rats. MSG lesioning resulted in an enhanced response of corticosterone to restraint stress (1309 ± 92 ng/ml compared with 628 ± 125 ng/ml in sham-lesioned animals), while ACTH responses to restraint stress in MSG-lesioned and sham-MSG groups were not significantly different (160 ± 24 pg/ml and 167 ± 24 pg/ml respectively). These data suggest that MSG-lesioned rats have an increased adrenocortical sensitivity. In rats subjected to the chronic osmotic stimulus of drinking 2% saline for 12 days, plasma ACTH levels were significantly reduced (15 ± 5 pg/ml) and the ACTH and corticosterone responses to restraint stress were eliminated. ACTH levels were also reduced in MSG-treated animals given 2% saline and the ACTH response to acute stress remained absent in these animals. However, a robust corticosterone response to restraint stress was observed in saline-treated MSG-lesioned rats. These data demonstrate that MSG lesioning results in elevated basal and stress-induced plasma corticosterone, and restores the adrenocortical response to stress which is absent in chronically osmotically stimulated rats. The evidence is consistent with the suggestion that MSG lesions a pathway involved in tonic inhibition of the HPA axis. In addition, the adrenocortical sensitivity to ACTH and other secretagogues may be increased in MSG-treated animals. Journal of Endocrinology (1994) 141, 497–503

scholarly journals SAT-124 Optimization of Experimental Conditions for Mimicking Hypoxia in Cultured Breast Cancer Cells by Using Cobalt(II) Chloride (CoCl2)

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Karin Chen ◽  
Leo Satlof ◽  
Udithi Kothapalli ◽  
Noah Ziluck ◽  
Maribel Lema ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cell Apoptosis ◽  
Breast Cancer Cells ◽  
Nuclear Translocation ◽  
Breast Cancer Cell Lines ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Experimental Conditions

Abstract Hypoxia is a common phenomenon in solid tumor development caused by a decrease in either oxygen concentration or oxygen pressure as a result of rapid tumor cell growth. Hypoxia is characterized by stabilization of the alpha subunit of the hypoxia-inducible factor (HIF-1α) and its nuclear translocation and heterodimerization with HIF-1β. Activation of this signaling pathway involves multiple downstream effectors including carbonic anhydrase 9 (CA9, s. CAIX). A reliable method to mimic hypoxia utilizes cobalt(II) chloride (CoCl2), which directly induces the expression of HIF-1α. The aim of this study was to optimize the experimental conditions for CoCl2 treatment of breast cancer cells in vitro using three human breast cancer cell lines (MDA-MB-231, T-47D, and MCF-7 cells). We performed time- and concentration-response experiments, using various concentrations of CoCl2 (50, 100, 200, and 300 μM) for 24 and 48 hours, and measured the expression of HIF-1α and CA9 by qRT-PCR and Western blot analyses. Results demonstrated that CoCl2 downregulated HIF-1α mRNA levels but upregulated CA9 mRNA levels in a concentration- and time-dependent manner. Concomitantly, CoCl2 treatment resulted in a significant induction of HIF-1α protein levels. We further investigated the effect of the CoCl2 concentrations listed above on cell apoptosis using an in situ apoptosis detection kit. The results demonstrated that concentrations of CoCl2 up to 100 μM had no significant effect on cell apoptosis.

scholarly journals Secretagogin Mediates the Regulatory Effect of Electroacupuncture on Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Surgical Trauma

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Mizhen Zhang ◽  
Jingxian Sun ◽  
Yu Wang ◽  
Zhanzhuang Tian
Keyword(s):  
Hpa Axis ◽  
Plasma Corticosterone ◽  
Control Group ◽  
Surgical Trauma ◽  
Mrna Levels ◽  
Hypothalamic Pituitary Adrenal ◽  
Protein Levels ◽  
Polymerase Chain ◽  
Hepatectomy Group

Electroacupuncture (EA) improves hypothalamic-pituitary-adrenal (HPA) axis disorder by reducing corticotropin-releasing hormone (CRH) synthesis and release in the paraventricular nucleus (PVN). However, the potential mechanism underlying CRH regulation remains unclear. Secretagogin (SCGN) is closely related to stress and is involved in regulating the release of CRH. We hypothesized that SCGN in the PVN might trigger the HPA system and be involved in EA-mediated modulation of HPA dysfunction caused by surgical trauma. Serum CRH and adrenocorticotropic hormone (ACTH) and plasma corticosterone (CORT) levels at 6 h and 24 h after hepatectomy were determined by radioimmunoassay. CRH and SCGN protein levels in the PVN were detected by western blot and immunofluorescence, and CRH and SCGN mRNA levels in the PVN were determined by means of real-time polymerase chain reaction (RT-PCR) and in situ hybridization (ISH). Our studies showed that serum CRH, ACTH, and CORT levels and PVN CRH expression were significantly increased at 6 h and 24 h after hepatectomy in the hepatectomy group compared with the control group, and those in the EA+hepatectomy group were decreased compared with those in the hepatectomy group. The protein and mRNA levels of SCGN in the PVN were also increased after hepatectomy, and their expression in the EA+hepatectomy group was decreased compared with that in the hepatectomy group. When SCGN expression in the PVN was functionally knocked down by a constructed CsCI virus, we found that SCGN knockdown decreased the serum CRH, ACTH, and CORT levels in the SCGN shRNA+hepatectomy group compared with the hepatectomy group, and it also attenuated CRH expression in the PVN. In summary, our findings illustrated that EA normalized HPA axis dysfunction after surgical trauma by decreasing the transcription and synthesis of SCGN.

scholarly journals The Effects of Estrogen and Progesterone on Corticotropin-Releasing Hormone and Arginine Vasopressin Messenger Ribonucleic Acid Levels in the Paraventricular Nucleus and Supraoptic Nucleus of the Rhesus Monkey

Endocrinology ◽  
1999 ◽  
Vol 140 (5) ◽  
pp. 2191-2198 ◽  
Author(s):  
Brenda N. Roy ◽  
Robert L. Reid ◽  
Dean A. Van Vugt
Keyword(s):  
In Situ Hybridization ◽  
Rhesus Monkey ◽  
Hpa Axis ◽  
Paraventricular Nucleus ◽  
Arginine Vasopressin ◽  
Supraoptic Nucleus ◽  
Mrna Levels ◽  
Ovarian Steroids ◽  
Messenger Ribonucleic Acid

Abstract Ovarian steroids increase hypothalamic-pituitary-adrenal (HPA) axis activity and sensitize the hypothalamic-pituitary-ovarian (HPO) axis to stress-induced inhibition. The present study investigated the effect of ovarian steroids on CRH and arginine vasopressin (AVP) messenger RNA (mRNA) levels in the rhesus monkey hypothalamus, as both neuropeptides have been shown to stimulate the HPA axis and inhibit the HPO axis in this species. This was accomplished by measuring CRH and AVP mRNA in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) by in situ hybridization histochemistry. Menstrual cycles were simulated in ovariectomized (OVX) rhesus monkeys by sequential addition and removal of SILASTIC brand (Dow Corning Corp.) tubing containing either 17β-estradiol (E2) or progesterone (P4). On the morning of day 11 of the simulated follicular phase (E2 alone) or day 21 of the luteal phase (E2 + P4), animals were anesthetized, and the brains were perfused with paraformaldehyde via the carotid artery. Coronal sections (30 μm) were cut, and mRNA for CRH and AVP in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) were semiquantified by in situ hybridization. CRH mRNA in the PVN of E2-replaced OVX animals (n = 7) was 2-fold greater than that in untreated OVX controls (n = 4), whereas CRH mRNA after E2 + P4 (n = 4) was no different from that in controls (optical density ± sem, 0.38 ± 0.06, 0.13 ± 0.08, and 0.14 ± 0.09 for OVX + E2, OVX + E2 + P4, and OVX, respectively; P = 0.02). CRH in the SON was undetectable. In contrast to CRH, AVP mRNA in the PVN and the SON was similar in the three treatment groups. We conclude that E2 and E2 + P4 replacement to OVX monkeys exert different effects on CRH and AVP gene expression, as estrogen stimulation of CRH mRNA in the PVN was abrogated by progesterone, whereas no effect of ovarian steroids on AVP mRNA in either the PVN or SON was observed. We postulate that ovarian steroid regulation of CRH synthesis and release may in part explain the central nervous system mechanisms by which ovarian steroids affect the HPA and HPO axes during basal and stress conditions.

scholarly journals Vasopressin Administration into the Paraventricular Nucleus Normalizes Plasma Oxytocin and Corticosterone Levels in Brattleboro Rats

Endocrinology ◽  
2009 ◽  
Vol 150 (6) ◽  
pp. 2791-2798 ◽  
Author(s):  
Dóra Zelena ◽  
Kristina Langnaese ◽  
Ágnes Domokos ◽  
Ottó Pintér ◽  
Rainer Landgraf ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Stress Responses ◽  
Extracellular Fluid ◽  
Plasma Corticosterone ◽  
Forced Swimming ◽  
Male Rats ◽  
Congenital Absence ◽  
Mrna Levels ◽  
Intact Control ◽  
The Impact

Adult male rats of the Brattleboro strain were used to investigate the impact of the congenital absence of vasopressin on plasma adrenocorticotropin, corticosterone, and oxytocin concentrations as well as the release pattern of oxytocin within the hypothalamic paraventricular nucleus (PVN), in response to a 10-min forced swimming session. Measurement of adrenocorticotropin in plasma samples collected via chronically implanted jugular venous catheters revealed virtually identical stress responses for vasopressin-lacking Brattleboro (KO) and intact control animals. In contrast, plasma corticosterone and oxytocin levels were found to be significantly elevated 105 min after onset of the stressor in KO animals only. Microdialysis samples collected from the extracellular fluid of the PVN showed significantly higher levels of oxytocin both under basal conditions and in response to stressor exposure in KO vs. intact control animals accompanied by elevated oxytocin mRNA levels in the PVN of KO rats. These findings suggest that the increased oxytocin levels in the PVN caused by the congenital absence of vasopressin may contribute to normal adrenocorticotropin stress responses in KO animals. However, whereas the stressor-induced elevation of plasma oxytocin in KO rats may be responsible for their maintained corticosterone levels, oxytocin seems unable to fully compensate for the lack of vasopressin. This hypothesis was tested by retrodialyzing synthetic vasopressin into the PVN area concomitantly with blood sampling in KO animals. Indeed, this treatment normalized plasma oxytocin and corticosterone levels 105 min after forced swimming. Thus, endogenous vasopressin released within the PVN is likely to act as a paracrine signal to facilitate the return of plasma oxytocin and corticosterone to basal levels after acute stressor exposure.

scholarly journals TheKampoMedicine Yokukansan Decreases MicroRNA-18 Expression and Recovers Glucocorticoid Receptors Protein Expression in the Hypothalamus of Stressed Mice

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shoko Shimizu ◽  
Takashi Tanaka ◽  
Takashi Takeda ◽  
Masaya Tohyama ◽  
Shingo Miyata
Keyword(s):  
Hpa Axis ◽  
Stress Responses ◽  
Glucocorticoid Receptors ◽  
Psychological Symptoms ◽  
Plasma Corticosterone ◽  
Mrna Levels ◽  
Stress Exposure ◽  
Protein Levels ◽  
Hpa Axis Activity ◽  
The Brain

It is well known that glucocorticoid receptor (GR) signaling regulates the hypothalamic-pituitary-adrenal (HPA) axis, and GR expression level is associated with HPA axis activity. Recent studies revealed that microRNA- (miR-) 18 and/or 124a are candidate negative regulators of GR in the brain. TheKampomedicine Yokukansan (YKS) can affect psychological symptoms such as depression and anxiety that are associated with stress responses. In this study, we evaluated the effect of YKS on miR-18 and 124a and GR levels in mice exposed to stress. We found that YKS pretreatment normalized elevated plasma corticosterone levels in stress-exposed mice. In addition, GR mRNA levels were downregulated in the brain following stress exposure. While miR-124a expression levels were not altered in the hypothalamus of stress-exposed mice, miR-18 levels decreased in the hypothalamus of YKS-pretreated mice after stress exposure. Finally, GR protein levels in the paraventricular nucleus (PVN) of the hypothalamus after stress exposure recovered in YKS-pretreated mice. Collectively, these data suggest that YKS normalizes GR protein levels by regulating miR-18 expression in the hypothalamus, thus normalizing HPA axis activity following stress exposure.

scholarly journals Requirement of Cannabinoid Receptor Type 1 for the Basal Modulation of Hypothalamic-Pituitary-Adrenal Axis Function

Endocrinology ◽  
2007 ◽  
Vol 148 (4) ◽  
pp. 1574-1581 ◽  
Author(s):  
Daniela Cota ◽  
Michel-Alexander Steiner ◽  
Giovanni Marsicano ◽  
Cristina Cervino ◽  
James P. Herman ◽  
...  
Keyword(s):  
Hpa Axis ◽  
Paraventricular Nucleus ◽  
Cannabinoid Receptor ◽  
Endocannabinoid System ◽  
Receptor Type ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Receptor Mrna ◽  
Cannabinoid Receptor Type 1

The endocannabinoid system affects the neuroendocrine regulation of hormone secretion, including the activity of the hypothalamus-pituitary-adrenal (HPA) axis. However, the mechanisms by which endocannabinoids regulate HPA axis function have remained unclear. Here we demonstrate that mice lacking cannabinoid receptor type 1 (CB1−/−) display a significant dysregulation of the HPA axis. Although circadian HPA axis responsiveness is preserved, CB1−/− mice are characterized by an enhanced circadian drive on the HPA axis, resulting in elevated plasma corticosterone concentrations at the onset of the dark as compared with wild-type (CB1+/+) littermates. Moreover, CB1−/−-derived pituitary cells respond with a significantly higher ACTH secretion to CRH and forskolin challenges as compared with pituitary cells derived from CB1+/+ mice. Both CBL−/− and CB1+/+ mice properly respond to a high-dose dexamethasone test, but response to low-dose dexamethasone is influenced by genotype. In addition, CB1−/− mice show increased CRH mRNA levels in the paraventricular nucleus of the hypothalamus but not in other extrahypothalamic areas, such as the amygdala and piriform cortex, in which CB1 and CRH mRNA have been colocalized. Finally, CB1−/− mice have selective glucocorticoid receptor mRNA down-regulation in the CA1 region of the hippocampus but not in the dentate gyrus or paraventricular nucleus. Conversely, mineralocorticoid receptor mRNA expression levels were found unchanged in these brain areas. In conclusion, our findings indicate that CB1 deficiency enhances the circadian HPA axis activity peak and leads to central impairment of glucocorticoid feedback, thus further outlining the essential role of the endocannabinoid system in the modulation of neuroendocrine functions.

scholarly journals Corticosterone-dependent metabolic and neuroendocrine abnormalities in obese Zucker rats in relation to feeding

2005 ◽  
Vol 288 (1) ◽  
pp. E254-E266 ◽  
Author(s):  
Martine Duclos ◽  
Elena Timofeeva ◽  
Chantal Michel ◽  
Denis Richard
Keyword(s):  
Food Deprivation ◽  
Hpa Axis ◽  
Stress Reaction ◽  
Whole Body ◽  
Zucker Rats ◽  
Mrna Levels ◽  
Experimental Conditions ◽  
Metabolic Defects ◽  
Obese Rats ◽  
Obese Zucker Rats

The obese Zucker ( fa/fa) rat is characterized by hyperphagia, hyperinsulinemia, an increase in fat deposition, and a hyperactivity in the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis in fa/fa rats is hypersensitive to stressful experimental conditions. Food deprivation even leads to a stress reaction in obese fa/fa rats. The present study was conducted to investigate the role of corticosterone in obese rats on the basal, fasting, and postprandial metabolic rate as well as on the central expression of the thyrotropin-releasing hormone (TRH) in these conditions. In addition, the study was aimed at clarifying whether the high levels of corticosterone in obese rats are responsible for the induction of the stress reaction to food deprivation in these animals. The present results demonstrate that whole body fat oxidation and postprandial metabolic responses in obese Zucker rats were improved by adrenalectomy (ADX). At the level of the central nervous system, ADX reversed a decrease in TRH mRNA expression in the paraventricular hypothalamus (PVH) detected in fasting animals. Considering all feeding conditions, the obese rats demonstrated lower TRH mRNA levels compared with lean animals. ADX resulted in an enhanced postprandial activation of the parvocellular PVH. In contrast, the magnocellular part of the PVH was less responsive to refeeding in ADX animals. Finally, ADX failed to prevent the stress response of obese rats to food deprivation. The present results provide evidence that the removal of adrenals resolve some of the metabolic defects encountered in obese Zucker rats. They also demonstrate that not all the abnormalities of the obese Zucker rats are attributable to the hyperactivity of the HPA axis.

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