Environmental enrichment modulates HPA axis reprogramming in adult male rats exposed to early adolescent stress

Glucocorticoids are essential for normal hypothalamic-pituitary-adrenal (HPA) axis activity; however, recent studies warn that exposure to excess endogenous or synthetic glucocorticoid during a specific period of prenatal development adversely affects HPA axis stability. We administered dexamethasone (DEX) to pregnant rats during the last week of gestation and investigated subsequent HPA axis regulation in adult male offspring in unrestrained and restraint-stressed conditions. With the use of real-time PCR and RIA, we examined the expression of regulatory genes in the hippocampus, hypothalamus, and pituitary, including corticotropin-releasing hormone (CRH), arginine vasopressin (AVP), glucocorticoid receptors (GR), mineralcorticoid receptors (MR), and 11-β-hydroxysteroid dehydrogenase-1 (11β-HSD-1), as well as the main HPA axis hormones, adrenal corticotropic hormone (ACTH) and corticosterone (CORT). Our results demonstrate that the DEX-exposed group exhibited an overall change in the pattern of gene expression and hormone levels in the unrestrained animals. These changes included an upregulation of CRH in the hypothalamus, a downregulation of MR with a concomitant upregulation of 11β-HSD-1 in the hippocampus, and an increase in circulating levels of both ACTH and CORT relative to unrestrained control animals. Interestingly, both DEX-exposed and control rats exhibited an increase in pituitary GR mRNA levels following a 1-h recovery from restraint stress; however, the increased expression in DEX-exposed rats was significantly less and was associated with a slower return to baseline CORT compared with controls. In addition, circulating levels of ACTH and CORT as well as hypothalamic CRH and hippocampal 11β-HSD-1 expression levels were significantly higher in the DEX-exposed group compared with controls following restraint stress. Taken together, these data demonstrate that late-gestation DEX exposure in rats is associated with persistent changes in both the modulation of HPA axis activity and the HPA axis-mediated response to stress.

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Chronic Intermittent Ethanol Exposure in Early Adolescent and Adult Male Rats: Effects on Tolerance, Social Behavior, and Ethanol Intake

Alcoholism Clinical and Experimental Research ◽

10.1111/j.1530-0277.2011.01474.x ◽

2011 ◽

pp. no-no ◽

Cited By ~ 8

Author(s):

Margaret Broadwater ◽

Elena I. Varlinskaya ◽

Linda P. Spear

Keyword(s):

Social Behavior ◽

Adult Male ◽

Ethanol Exposure ◽

Ethanol Intake ◽

Male Rats ◽

Early Adolescent ◽

Chronic Intermittent Ethanol ◽

Chronic Intermittent Ethanol Exposure

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The Effect of Neonatal Maternal Stress on Plasma Levels of Adrenocorticotropic Hormone, Corticosterone, Leptin, and Ghrelin in Adult Male Rats Exposed to Acute Heterotypic Stressor

Physiological Research ◽

10.33549/physiolres.933530 ◽

2016 ◽

pp. S557-S566 ◽

Cited By ~ 6

Author(s):

A. HOLUBOVÁ ◽

A. ŠTOFKOVÁ ◽

J. JURČOVIČOVÁ ◽

R. ŠLAMBEROVÁ

Keyword(s):

Hpa Axis ◽

Adult Male ◽

Plasma Levels ◽

Adrenocorticotropic Hormone ◽

Acute Stress ◽

Male Rats ◽

Lower Sensitivity ◽

Male Progeny ◽

Swimming Stress ◽

Plasma Leptin

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is important for maintenance of homeostasis during stress. Recent studies have shown a connection between the HPA axis and adipose tissue. The present study investigated the effect of acute heterotypic stress on plasma levels of adrenocorticotropic hormone (ACTH), corticosterone (CORT), leptin, and ghrelin in adult male rats with respect to neonatal maternal social and physical stressors. Thirty rat mothers and sixty of their male progeny were used. Pups were divided into three groups: unstressed control (C), stressed by maternal social stressor (S), stressed by maternal social and physical stressors (SW). Levels of hormones were measured in adult male progeny following an acute swimming stress (10 min) or no stress. ELISA immunoassay was used to measured hormones. The ACTH and CORT levels were significantly increased in all groups of adult progeny after acute stress; however, CORT levels were significantly lower in both neonatally stressed groups compared to controls. After acute stress, plasma leptin levels were decreased in the C and SW groups but increased in the S group. The data suggest that long-term neonatal stressors lead to lower sensitivity of ACTH receptors in the adrenal cortex, which could be a sign of stress adaptation in adulthood. Acute stress in adult male rats changes plasma levels of leptin differently relative to social or physical neonatal stressors.

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