Corticoid Response to Stress in the Steroid-Inhibited Rat

Schapiro, Shawn; Geller, Edward; Eiduson, Samuel

doi:10.3181/00379727-109-27383

Cited by 26 publications

(13 citation statements)

References 2 publications

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“…1 and 2) show that the maximal stress-induced corticosterone concentration on day 1 of treatment was reduced in all groups receiving the 5 fig dosage and in the young groups receiving the 1 fig injection. This reduction in adrenocortical stress responsiveness was particularly pronounced in the young groups of both sexes. This incomplete block of high-intensity stress activation of the adrenal cortex by in jection of glucocorticoids agrees with the observations of Shapiro et al [1962], H odges and J ones [1963], Smelik [1963], and others. When the dexamethasone suppression was continued for 14 days, the degree of adrenocortical inhibition was consistently higher from the 5 yMg/100 g body weight dose than from the 1 fig/lOO g treatment for all experimental groups and the reduction was greater with increased duration of the treatment.…”

Section: Discussionsupporting

confidence: 80%

Chronic and Acute Dexamethasone Suppression of Stress Activation of the Adrenal Cortex in Young and Aged Rats

Riegle

Hess

1972

Neuroendocrinology

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Adrenocortical responsiveness to ether vapor stress was measured in young adult (4–6 months) and aged (22–32 months) rats subjected to acute and chronic treatments with dexamethasone. Daily administration of 25 µg dexamethasone/100 g body weight for 28 days markedly reduced adrenocortical responsiveness to stress in all groups. Both young and aged groups returned to normal stress responsiveness after cessation of the treatment. Injection of 5 µg dexamethasone/100 g body weight for 14 days produced greater adrenocortical inhibition than did 1 µg treatment in all groups. Aged groups of both sexes showed less suppression of stress activation of the adrenal cortex on days 1, 4, 8, and 14 of both the 1 and 5 µg/100 g body weight treatment regimes. Adrenocortical responsiveness to stress at 4, 7, and 15 min after animal disturbance was also less inhibited in aged male and female rats receiving a single 5 µg/100 g body weight injection of dexamethasone than in similar groups of young animals. These data indicate that the aged rat has a substantial decrease in the sensitivity of its adrenocortical control mechanism to feedback inhibition, which may play a substantial role in the homeostatic alterations recognized to occur with increasing age.

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Section: Discussionsupporting

confidence: 80%

Chronic and Acute Dexamethasone Suppression of Stress Activation of the Adrenal Cortex in Young and Aged Rats

Riegle

Hess

1972

Neuroendocrinology

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“…Thus, maternal sickness behavior remained at least 3 days after the treatment, thus reaching the postnatal period. Since it is known that newborn rats pass through a stressnonresponsive period for the first 10 days after birth [57] , a stress demasculinizing effect was not the cause of the sexual disruption observed here.…”

Section: Discussionmentioning

confidence: 74%

Prenatal Lipopolysaccharide Exposure Affects Maternal Behavior and Male Offspring Sexual Behavior in Adulthood

Bernardi

Kirsten

Matsuoka

et al. 2009

Neuroimmunomodulation

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Objective: This study investigates the effects of prenatal lipopolysaccharide (LPS) exposure on the maternal behavior of pregnant rats and the physical development and sexual behavior of their male offspring in adulthood. Methods: For two experiments, pregnant rats were injected with LPS (250 μg/kg, i.p.) on gestation day (GD) 21. In the first experiment, the maternal behavior (postnatal day, PND, 6) and the dam’s open-field general activity (PND7) were evaluated. In the second experiment, the maternal pre- and postnatal parameters, the pup’s development, the offspring’s sexual behavior in adulthood, and the pup’s organ weights were assessed. Results: Compared to the control group, the LPS-treated dams presented reduced maternal behavior, decreased general activity, a smaller body weight difference between GD21 and PND1, a greater number of perinatal deaths, and smaller litters. For the male pups, LPS treatment resulted in a decreased body weight on PND2, whereas the anogenital distance and the day of testis descent were not modified. The male sexual behavior was impaired by prenatal LPS. Particularly the number of ejaculating animals was reduced. The testis weight was also lower in the prenatally LPS-treated rats than in the control rats. Conclusion: We propose that prenatal LPS exposure on GD21 acts as an imprinting factor that interferes with the programming of brain sexual determination in offspring.

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“…In the pig, basal plasma total cortisol concentrations do not differ between postnatal days 3 and 42 (Kattesh et al 1990), whereas plasma total cortisol concentrations are increasing over this period in the rat (Meaney et al 1985b). In addition, the rat shows a stress hyporesponsivity during the first 2 weeks of life compared with the plasma corticosterone and ACTH responses to identical stressors in adult rats (Shapiro et al 1962, Walker et al 1991, Viau et al 1996. To our knowledge, the existence of a stress-hyporesponsive period in neonatal pigs, compared with adult pigs, has not been examined.…”

Section: Discussionmentioning

confidence: 99%

Neonatal handling permanently alters hypothalamic-pituitary- adrenal axis function, behaviour, and body weight in boars

Weaver¹,

Aherne²,

Meaney³

et al. 2000

Journal of Endocrinology

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Neonatal handling permanently alters hypothalamicpituitary-adrenal axis (HPA) function in rats. In the rat, this treatment increases hippocampal glucocorticoid receptors (GR) and dampens plasma ACTH and corticosterone responses to stressors. The objectives of this study were to determine whether neonatal handling of pigs would effect permanent changes in plasma corticosteroid binding capacity (CBG), basal or stressor-induced plasma cortisol and ACTH concentrations, brain or pituitary GR levels, dexamethasone suppression of plasma cortisol and ACTH concentrations, behaviour in an open field-test pen, and body weights. Twelve litters of pigs were randomly assigned to either neonatal handling or no disturbance. Handled litters were removed from the farrowing crate for 10 min per day for the first 14 days of life. Male pigs were kept for the study and the boars were weighed monthly. At 7 months of age, boars were tested for locomotory behaviour in an open field-test pen. The boars were implanted with indwelling ear-vein catheters and blood samples were obtained basally, during and after application of a nose snare, and after 0·04 mg/kg dexamethasone. Boars were killed and blood samples were obtained and the brain and pituitary glands collected. Handled boars had greater (P<0·05) plasma CBG binding and lower basal total (P<0·05) and calculated free (P<0·03) plasma cortisol concentrations. No significant differences between treatments were found in plasma ACTH or cortisol responses to a nose-snare stressor; however, when killed, handled boars had greater (P<0·02) plasma ACTH concentrations. Handled and non-handled boars did not differ in plasma ACTH or cortisol responses to dexamethasone. There was no treatment effect on GR expression in the pituitary gland, frontal cortex, hippocampus, or hypothalamus. Behaviourally, the handled boars had higher (P<0·03) locomotor scores over inner squares and a lower (P<0·05) ratio of outer:inner squares entered in open field-tests. During the first 7 months of life, body weights were lower (P<0·004) for handled boars. In conclusion, neonatal handling permanently altered HPA function in pigs, but in a manner dissimilar to that found in the rat. These changes induced in the pig were not beneficial for commercial production with respect to body weight.

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Corticoid Response to Stress in the Steroid-Inhibited Rat

Cited by 26 publications

References 2 publications

Chronic and Acute Dexamethasone Suppression of Stress Activation of the Adrenal Cortex in Young and Aged Rats

Chronic and Acute Dexamethasone Suppression of Stress Activation of the Adrenal Cortex in Young and Aged Rats

Prenatal Lipopolysaccharide Exposure Affects Maternal Behavior and Male Offspring Sexual Behavior in Adulthood

Neonatal handling permanently alters hypothalamic-pituitary- adrenal axis function, behaviour, and body weight in boars

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