Immunity is hypothesized to share limited resources with other physiological functions and this may partly account for the fitness costs of reproduction. Previous studies have shown that the acquired immunity of female common eider ducks (Somateria mollissima) is suppressed during their incubation, during which they entirely fast. Corticosterone was proposed to be an underlying physiological me...

Introduction: Psychological stresses influence brain functions such as learning and memory. Environmental factors like types and durations of stress affect brain responsiveness. This study investigated the effects of two subchronic social and isolation stresses on learning, memory, adrenal glands weight and corticosterone levels in the hippocampus and frontal cortex. Methods: Eighteen male ...

Introduction: The role of different parts of the extended amygdala in metabolic signs of stress is not well understood. In the present study, we decided to evaluate the impact of the shell part of nucleus accumbens (NAc) on metabolic disturbance induced by electro foot shock stress using transient inactivation method in the rat.  Methods: Male Wistar rats (W: 230-250 g) were canuulated un...

The mechanisms underlying honest signal expression remain elusive and may involve the integration of social and physiological costs. Corticosterone is a socially modulated metabolic hormone that mediates energy investment and behavior and may therefore function to deter dishonest signal expression. We examined the relationship between corticosterone and green badge coloration in male sand lizar...

Mature male rats with isoproterenol-induced myocardial infarction and normal controls were injected intravenously with [1, 2-H] corticosterone (H corticosterone). Blood and tissue samples (liver, brain, adrenal glands, "normal" and necrotic areas of the heart) were collected 15, 30, and 45 minutes after tracer injection. Gross and histopathological changes were noted. The metabolic clearance ra...

One of the mechanisms through which regular exercise contributes to weight maintenance could be by reducing intake and preference for high-fat (HF) diets. Indeed, we previously demonstrated that wheel-running rats robustly reduced HF diet intake and preference. The reduced HF diet preference by wheel running can be so profound that the rats consumed only the chow diet and completely avoided the...

The effects of age, handling-induced stress, yolk androgens, and body condition on plasma corticosterone levels were investigated in free-living nestling American kestrels, Falco sparverius, a semialtricial falcon species. In an observational study, corticosterone levels varied with age and handling time. Specifically, corticosterone was low until age 15 days and then rose from age 20 through 2...

Maternal stress in birds can have permanent transgenerational effects through the transmission of stress hormones to offspring via the egg yolk. Previous studies have shown that White Leghorn hens show a heightened response to stress compared with Hy-Line Brown hens, producing significantly more corticosterone and displaying longer bouts of tonic immobility after handling, whereas baseline leve...

Corticosterone is synthesized in the adrenal glands and is circulated throughout the body to perform regulatory functions in various tissues. The testis is known to synthesize and secrete testosterone and other androgens. We developed an accurate method to measure steroid content using liquid chromatography-mass spectrometry analysis. In the present study, significant levels of the precursor co...

Neurochemicals such as serotonin convey information about behavioral context to sensory processing. In the auditory system, serotonin modulates the responses of neurons in the inferior colliculus (IC) to acoustic stimuli, including communication vocalizations. Levels of extracellular serotonin in the IC can change rapidly in response to stressful situations such as social challenge and limited ...