Pituitary-Adrenal Function in the Rat After Gonadectomy and Gonadal Hormone Replacement1

Kitay, Julian I.

doi:10.1210/endo-73-2-253

Cited by 308 publications

(133 citation statements)

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“…However, a reduction in free corticosterone would reduce, not enhance, glucocorticoid feedback, so it is unlikely that changes in corticosterone binding globulin contributed to our findings. Another possibility is that estradiol may enhance corticosterone feedback by stimulating corticosterone production at the adrenal or by reducing corticosterone metabolism (Kitay 1963;Lo et al 2000). However, we found no evidence of enhanced basal corticosterone levels in estrogen treated rats, or any reduction in basal corticosterone in rats treated with estradiol antagonists.…”

Section: Discussioncontrasting

confidence: 67%

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Effects of Estrogen Antagonists and Agonists on the ACTH Response to Restraint Stress in Female Rats

Young

Altemus

Parkison

et al. 2001

Neuropsychopharmacology

159

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Previous studies have found that female rats are less sensitive than males to hypothalamic-pituitary-adrenal axis feedback inhibition by exogenous glucocorticoid administration. To determine whether estrogen contributesSex differences in HPA axis regulation in rodents have been demonstrated by a number of investigators, and these differences are generally attributed to activational effects of gonadal steroids on elements of the hypothalamic-pituitary-adrenal axis in females, although there is also evidence that testosterone inhibits HPA axis activity in males (Handa et al. 1994). Female rats have higher levels of total plasma corticosterone (Kitay 1963). Female rats also have higher plasma corticosterone binding globulin levels, which likely contributes to findings of similar free corticosterone levels in male and female rats. Compared with male rats, female rats also have a greater ACTH response to stress, faster onset of corticosterone secretion after stress, and a faster rate of rise of corticosterone (Le Mevel et al. 1979;Jones et al. 1972; Young 1996). Several studies suggest that estradiol plays a role in enhanced stress responses in female

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Section: Discussioncontrasting

confidence: 67%

“…Female rats have higher levels of total plasma corticosterone (Kitay 1963). Female rats also have higher plasma corticosterone binding globulin levels, which likely contributes to findings of similar free corticosterone levels in male and female rats.…”

mentioning

confidence: 79%

Effects of Estrogen Antagonists and Agonists on the ACTH Response to Restraint Stress in Female Rats

Young

Altemus

Parkison

et al. 2001

Neuropsychopharmacology

159

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“…The most straightforward mechanism would be for the sex steroids to affect adrenocortical sensitivity to ACTH (Atkinson and Waddell, 1997). A stimulating action of oestrogens and an inhibiting action of testosterone on the adrenal have been previously proposed in rats (Kitay, 1963;Nowak et al, 1995). Therefore, one of our target genes in experiment 2 was of the ACTH receptor (MC2R).…”

Section: Adrenal Weightmentioning

confidence: 99%

Sex steroid modulation of cortisol secretion in sheep

Lier

Carriquiry

Meikle

2014

Animal

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There is strong evidence that the gonads modulate the hypothalamic-pituitary-adrenal axis. To investigate these sex differences at the adrenal glands of sheep we compared the cortisol response to ACTH (experiment 1) and measured the relative expression of oestrogen receptor alpha (ERS1), androgen receptor (AR), melanocortin 2 receptor (MC2R) and steroid acute regulatory protein (STAR) mRNA in adrenal glands (experiment 2) of gonadectomised rams and ewes either with or without sex steroid replacement. In experiment 1 six castrated adult rams and four ovariectomised adult ewes were used in two ACTH trials. On each trial blood samples were taken every 15 min for 4 h through an indwelling jugular catheter and each animal received 0.5 mg of an ACTH analogue i.v., immediately after the sample at 1 h from the beginning of the trial. Four days after the first trial the males received 100 mg of Testosterone Cyclopentilpropionate (TC) i.m. and the females received 2.5 mg of Oestradiol Benzoate (EB) i.m. At 72 h after TC or EB administration the second trial was performed. In experiment 2 the adrenal glands were obtained from gonadectomised adult rams (n = 8) and adult ewes (n = 8). Four rams received 100 mg of TC i.m. and four females received 0.5 mg of EB i.m. Blood samples were taken at 0, 12, 24, 48 and 72 h relative to steroid replacement and the animals were thereafter slaughtered. Cortisol, testosterone and 17β-oestradiol were determined by radioimmunoanalysis. The transcripts of ERS1, AR, MC2R and STAR were determined by real-time reverse transcription PCR in adrenal tissue. Cortisol secretion was higher in female sheep than in male sheep, and higher in EB-treated than non-treated ewes. No difference in cortisol secretion was observed between TC-treated and non-treated rams. Gonadectomised rams treated with TC presented greater AR mRNA and MC2R mRNA expression than males without the steroid replacement. Gonadectomised ewes treated with EB tended to present lower AR mRNA than the ones without steroid replacement. Gonadectomised rams with TC also had greater AR mRNA, ERS1 mRNA and MC2R mRNA expression than ewes treated with EB. The relative amount of STAR transcript was not different among the different groups. The results confirm sex differences in ACTH-induced cortisol secretion in sheep, as well as in the expression of the receptor proteins for both 17β-oestradiol and testosterone in the sheep adrenal gland. However, the underlying mechanisms for sex steroid modulation remain unresolved.Keywords: sex steroids, gonadectomy, adrenal, receptors, sheep ImplicationsDifferent stressors result in different responses from the hypothalamus-pituitary-adrenal (HPA) axis and stress can reduce reproductive performance in mammals. Considering the different roles of males and females in reproduction, it is reasonable to think that each sex has its own strategy for dealing with the effects of stress. There is abundant evidence that the gonads affect the way the HPA axis responds to stress. Understanding the regulatory pathways of...

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“…Alternatively, saline -injected females may have become 15 desinsitised to ACTH during the four day injection period whilst sensitivity was 16 maintained in oestrogen-treated females. In mammals, oestrogen can increase cor tisol 17 production by the adrenals (Kitay, 1963), and the response to ACTH is most 18 pronounced when estrogen levels are highest, such as at pro -oestrous (Viau and 19 Meaney, 1991 …”

Section: Introductionmentioning

confidence: 99%

Does adrenal responsiveness vary with sex and reproductive status in Egernia whitii, a viviparous skink?

Cartledge

Jones

2007

General and Comparative Endocrinology

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Pituitary-Adrenal Function in the Rat After Gonadectomy and Gonadal Hormone Replacement1

Cited by 308 publications

References 0 publications

Effects of Estrogen Antagonists and Agonists on the ACTH Response to Restraint Stress in Female Rats

Effects of Estrogen Antagonists and Agonists on the ACTH Response to Restraint Stress in Female Rats

Sex steroid modulation of cortisol secretion in sheep

Does adrenal responsiveness vary with sex and reproductive status in Egernia whitii, a viviparous skink?

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