Influence of reproductive state on pituitary-adrenal activity in the ewe

Bell, Michael; Wood, Charles E.; Keller‐Wood, Maureen; Kane, Cheikhou; Kluwe, C.; Manlove, E.; Taranovich, C.

doi:10.1016/0739-7240(91)90060-w

Cited by 66 publications

(46 citation statements)

References 29 publications

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“…Consistent with these findings, we also showed that sex and gonadal status affect the distribution of CRH, AVP and enkephalin in the paraventricular nucleus of sheep, providing a neuroanatomical basis for sex differences in the central regulation of the hypothalamo-pituitary adrenal axis [66]. Others have shown that steroids and reproductive state can affect the activity of the hypothalamo-pituitary adrenal axis in female sheep [100], but there were no comparisons with males. In a series of studies in ewes it was shown that progesterone inhibits ACTH stimulation of cortisol [101,102,103] and stress, induced secretion of cortisol estrogens and androgens influence hypothalamic concentrations of CRH and AVP [104], and that ovariectomy affects hypothalamo-pituitary adrenal axis responses to stress [105,106].…”

Section: The Role Of Sex Steroids and Reproductive State On Stress Resupporting

confidence: 76%

Sex Differences and the Role of Sex Steroids in Sympatho-Adrenal Medullary System and Hypothalamo-Pituitary Adrenal Axis Responses to Stress

Turner¹,

Keating²,

Tilbrook³

2012

Sex Steroids

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Section: The Role Of Sex Steroids and Reproductive State On Stress Resupporting

confidence: 76%

Sex Differences and the Role of Sex Steroids in Sympatho-Adrenal Medullary System and Hypothalamo-Pituitary Adrenal Axis Responses to Stress

Turner¹,

Keating²,

Tilbrook³

2012

Sex Steroids

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“…Plasma ACTH was measured by RIA, using an antibody to ACTH (1-39) (Bell et al 1991), and plasma cortisol concentration was measured using a commercially available enzyme immunoassay kit (EA 65, Oxford Biomedical, Oxford, MI, USA) that has minimal cross-reactivity with cortisone (2 . 08%).…”

Section: Discussionmentioning

confidence: 99%

Cardiac corticosteroid receptors mediate the enlargement of the ovine fetal heart induced by chronic increases in maternal cortisol

Reini¹,

Dutta²,

Wood³

et al. 2008

Journal of Endocrinology

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Previous studies have demonstrated that modest, physiologically relevant increases in maternal cortisol in late gestation result in enlargement of the fetal heart. In this study, we investigated the role of mineralocorticoid receptor (MR) or glucocorticoid receptor (GR) in this enlargement. Ewes with single fetuses were randomly assigned at w120 days of gestation to one of four groups: maternal cortisol infusion (1 mg/kg per day, cortisol); maternal cortisol infusion with fetal intrapericardial infusion of the MR antagonist (MRa) potassium canrenoate (600 mg/day; cortisolCMRa); maternal cortisol infusion with fetal intrapericardial infusion of the GR antagonist (GRa) mifepristone (50 mg/day, cortisolCGRa); and maternal saline infusion (control). At w130 days of gestation, fetal heart to body weight ratio and right ventricular (RV) and left ventricular (LV) free wall thicknesses were increased in the cortisol group when compared with control group. Fetal hearts from the cortisolCMRa group weighed significantly less, with thinner LV, RV, and interventricular septum walls, when compared with the cortisol group. Fetal hearts from the cortisolCGRa group had significantly thinner RV walls than the cortisol group. Fetal arterial pressure and heart rate were not different among groups at 130 days. Picrosirius red staining of fetal hearts indicated that the increased size was not accompanied by cardiac fibrosis. These results suggest that physiologic increases in maternal cortisol in late gestation induce fetal cardiac enlargement via MR and, to a lesser extent, by GR, and indicate that the enlargement is not secondary to an increase in fetal blood pressure or an increase in fibrosis within the fetal heart.

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“…3). Blood samples (8 ml) were collected into EDTA-treated tubes just prior to the start of the infusion and at every hour during the infusion.…”

Section: Methodsmentioning

confidence: 99%

“…Animals were induced with isoflurane inhalant and maintained using either isoflurane or halothane inhalant (1-3% in oxygen). Surgery was performed for the insertion of sterile polyvinyl catheters in the femoral arteries and veins of the ewes, as described previously (3). During a 5-day recovery period, the animals received twice daily intramuscular injections of ampicillin (1 g); body temperature was also monitored twice daily.…”

Section: Methodsmentioning

confidence: 99%

Differential effects of mineralocorticoid blockade on the hypothalamo-pituitary-adrenal axis in pregnant and nonpregnant ewes

Lingis

Richards

Keller‐Wood

2011

American Journal of Physiology-Endocrinology and Metabolism

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Lingis M, Richards EM, Keller-Wood M. Differential effects of mineralocorticoid blockade on the hypothalamo-pituitary-adrenal axis in pregnant and nonpregnant ewes. Am J Physiol Endocrinol Metab 300: E592-E599, 2011. First published January 4, 2011; doi:10.1152/ajpendo.00560.2010.-During pregnancy, plasma ACTH and cortisol are chronically increased; this appears to occur through a reset of hypothalamo-pituitary-adrenal (HPA) activity. We have hypothesized that differences in mineralocorticoid receptor activity in pregnancy may alter feedback inhibition of the HPA axis. We tested the effect of MR antagonism in pregnant and nonpregnant ewes infused for 4 h with saline or the MR antagonist canrenoate. Pregnancy significantly increased plasma ACTH, cortisol, angiotensin II, and aldosterone. Infusion of canrenoate increased plasma ACTH, cortisol, and aldosterone in both pregnant and nonpregnant ewes; however, the temporal pattern of these responses differed between these two reproductive states. In nonpregnant ewes, plasma ACTH and cortisol transiently increased at 1 h of infusion, whereas in pregnant ewes the levels gradually increased and were significantly elevated from 2 to 4 h of infusion. MR blockade increased plasma aldosterone from 2 to 4 h in the pregnant ewes but only at 4 h in the nonpregnant ewes. In both pregnant and nonpregnant ewes, the increase in plasma aldosterone was significantly related to the timing and magnitude of the increase in plasma potassium. The results indicate a differential effect of MR activity in pregnant and nonpregnant ewes and suggest that the slow changes in ACTH, cortisol, and aldosterone are likely to be related to blockade of MR effects in the kidney rather than to effects of MR blockade in hippocampus or hypothalamus.cortisol; adrenocorticotropic hormone; pregnancy; canrenoate; aldosterone IN STUDIES OF BOTH WOMEN (8) and ewes (3), basal plasma adrenocorticotropic hormone (ACTH) and cortisol have been shown to increase during pregnancy. The increase in adrenal steroid secretion is critical for normal pregnancy. Reduction of either maternal cortisol or maternal aldosterone results in alterations in maternal and fetal physiology (19 -21). We have hypothesized that there is a change in the regulation of basal ACTH in the pregnant state. Previous studies in our laboratory in adrenalectomized sheep have shown that the concentration for cortisol replacement required to normalize basal plasma ACTH is increased in pregnancy and that replacement of pregnant ewes with cortisol to plasma concentrations similar to those measured in nonpregnant ewes increases both basal and hypotension-stimulated ACTH release (23,26). On the other hand, in studies using adrenal-intact ewes, the inhibition of ACTH produced by raising plasma cortisol above resting levels is not different during pregnancy (23). Therefore, we have hypothesized that during pregnancy the "set point" of the negative feedback regulation by cortisol is increased, and/or a greater increase in cortisol is required in the pregnant s...

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Influence of reproductive state on pituitary-adrenal activity in the ewe

Cited by 66 publications

References 29 publications

Sex Differences and the Role of Sex Steroids in Sympatho-Adrenal Medullary System and Hypothalamo-Pituitary Adrenal Axis Responses to Stress

Sex Differences and the Role of Sex Steroids in Sympatho-Adrenal Medullary System and Hypothalamo-Pituitary Adrenal Axis Responses to Stress

Cardiac corticosteroid receptors mediate the enlargement of the ovine fetal heart induced by chronic increases in maternal cortisol

Differential effects of mineralocorticoid blockade on the hypothalamo-pituitary-adrenal axis in pregnant and nonpregnant ewes

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