Harsh weather can have devastating effects on both the survival and the breeding success of wild animals. Corticosterone, released in response to the stress caused by harsh conditions, may trigger physiological and behavioral changes that help ameliorate these effects. We examined three species of Arctic-breeding passerine birds for correlations between circulating plasma corticosterone levels ...

The present study was conducted to assess the effects of leptin on food intake and energy balance in the presence or absence of corticosterone. Three cohorts of C57BL/6 mice differing in their corticosterone status [nonadrenalectomized (intact), adrenalectomized (ADX), and ADX with corticosterone replacement] were infused with either saline or leptin at a dose of 150 μg ⋅ kg-1 ⋅ day-1. Througho...

The suprachiasmatic nucleus (SCN) is required for the daily rhythm of plasma glucocorticoids; however, the independent contributions from oscillators within the different subregions of the SCN to the glucocorticoid rhythm remain unclear. Here, we use genetically and neurologically intact, forced desynchronized rats to test the hypothesis that the daily rhythm of the glucocorticoid, corticostero...

We measured corticosterone in plasma collected from free-living AdClie Penguins (Pygoscelis adeliae) and made blood smears to count the ratio of heterophils to lymphocytes ( H a ) . Our objective was to categorize how these two measures of stress vary with potential stressors in the birds' environment. In penguins that were repeatedly sampled from three to eight times, repeated handling did not...

Although apoptotic cellular degeneration has been reported to be extremely rapid with the use of in vitro models, the time needed to clear apoptotic neurons in the in vivo brain is unknown. In this study we used a simple morphological approach to solve this problem. Four days after adrenalectomy (ADX), all of the operated rats morphologically displayed hippocampal granule cell apoptosis that wa...

The emergence of air breathing during amphibian metamorphosis requires significant changes to the brainstem circuits that generate and regulate breathing. However, the mechanisms controlling this developmental process are unknown. Because corticosterone plays an important role in the neuroendocrine regulation of amphibian metamorphosis, we tested the hypothesis that corticosterone augments fict...

Prolonged or excessive exposure to corticosterone leads to neuronal damages in the brain regions, including hippocampus. We reported that astrocyte-conditioned medium (ACM) protected the neurons of the primary hippocampal cultures against the corticosterone-induced damages. Corticosterone added to the cultures resulted in a significant number of TUNEL-positive cells. However, corticosterone-ind...

Chronic glucocorticoid exposure is known to cause depression and metabolic disorders. It is critical to improve abnormal metabolic status as well as depressive-like behaviors in patients with long-term glucocorticoid therapy. This study aimed to investigate the effects of resveratrol on the depressive-like behaviors and metabolic abnormalities induced by chronic corticosterone injection. Male I...

Stressful life events are important contributors to relapse in recovering cocaine addicts, but the mechanisms by which they influence motivational systems are poorly understood. Studies suggest that stress may "set the stage" for relapse by increasing the sensitivity of brain reward circuits to drug-associated stimuli. We examined the effects of stress and corticosterone on behavioral and neuro...

Endogenous glucocorticoids (GCs) have both stimulatory and suppressive effects on immune cells depending on the concentration. However, the mechanisms underlying the stimulatory effects of GCs remain elusive. Rat peritoneal macrophages were treated with different concentrations of corticosterone (0, 30 nM, 150 nM, and 3  μ M). To inhibit the glucocorticoid receptor (GR) activity, macrophages we...