Chronic stress--the key to parturition?

McMillen, I. C.; Phillips, I D; Ross, J. T.; Robinson, J. S.; Owens, Julie A.

doi:10.1071/rd9950499

Cited by 31 publications

(18 citation statements)

References 28 publications

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“…McMillen et al (33) also found that fetal plasma ACTH concentrations double between 120 and 136 d and 140 and 143 d gestation. In the current study, fetal plasma ACTH concentrations did not increase in the control group but doubled in the FX group on infusion d 7.…”

Section: Discussionmentioning

confidence: 93%

Chronic Maternal Fluoxetine Infusion in Pregnant Sheep: Effects on the Maternal and Fetal Hypothalamic-Pituitary-Adrenal Axes

Morrison¹,

Riggs

Chien

et al. 2004

Pediatr Res

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Depression during pregnancy is frequently treated with the selective serotonin reuptake inhibitor, fluoxetine (FX). FX increases serotonergic neurotransmission and serotonin plays a role in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. We have therefore investigated the effect of chronic administration of FX to the pregnant ewe on the maternal and fetal HPA axes. Nineteen late-gestation sheep were surgically prepared for chronic study of the fetus. FX (n ϭ 7, 98.5 g/kg/d) or sterile water (control, n ϭ 8) was administered to the ewe for 8 d by constant rate i.v. infusion with an initial FX bolus dose of 70 mg. Maternal and fetal plasma ACTH and cortisol concentrations were determined at 0700 h each day. Maternal plasma ACTH concentrations fell on infusion d 2, but no changes were observed in maternal plasma cortisol concentrations. Fetal plasma ACTH concentrations increased on infusion d 7, and fetal plasma cortisol concentrations increased on infusion d 6, 7, and 8 in the FX group. In addition, the regression coefficient for the relationship between fetal ACTH and cortisol levels was significantly greater in the FX group compared with the control group. Thus, maternal FX treatment increased fetal plasma cortisol concentration. These results are of particular interest in the context that exposure of the fetus to excess glucocorticoids at critical windows during development has been shown to increase the risk of poor health outcomes in later life. Clinical depression occurs in 5-15% of pregnant women (1). Treatment of depression during pregnancy is important to fetal outcome by preventing poor maternal self-care and nutrition, disturbed sleep, lack of prenatal care, increased exposure to alcohol and drugs, and a higher risk of suicide by the mother (1). Depression at 28 wk gestation is related to an increase in negative pregnancy outcome, including an increased risk of low-birth-weight newborns, preterm delivery, and small-forgestational-age newborns (2). FX is a SSRI that increases serotonergic neurotransmission and is prescribed clinically for the treatment of depression, obsessive-compulsive disorder, and bulimia (3). It and other SSRIs have become increasingly used for the treatment of depression in pregnancy because of their effectiveness and lower incidence of maternal side effects and wider safety margin compared with tricyclic antidepressants and monoamine oxidase inhibitors (4, 5). However, there have been several reports that use of these drugs during pregnancy can increase the incidence of adverse pregnancy outcomes, including preterm delivery, fetal growth restriction, and poor neonatal adaptation (5-8). There is also evidence for postnatal consequences of prenatal SSRI exposure, including reduced weight gain, slight delays in psychomotor development and motor movement control, and our own findings of reduced facial and heart rate responses to painful stimuli (9 -11). ABSTRACT40

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Section: Discussionmentioning

confidence: 93%

Chronic Maternal Fluoxetine Infusion in Pregnant Sheep: Effects on the Maternal and Fetal Hypothalamic-Pituitary-Adrenal Axes

Morrison¹,

Riggs

Chien

et al. 2004

Pediatr Res

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“…The maturation of the hypothalamo-pituitary adrenal axis in sheep clearly occurs very early during development, with this axis being functional even before birth (Brooks et al 1992, McMillen et al 1995, Matthews & Challis 1996, Reperant & Durand 1997, Challis et al 2001. Our results show that in both 1 and 8 week old male and female lambs the hypothalamo-pituitary adrenal axis was sufficiently mature to be capable of responding to the stress of tail docking, to treatment with ACTH and, in males, to the combined stress of tail docking and castration.…”

Section: Discussionmentioning

confidence: 99%

“…It has been shown that the hypothalamo-pituitary adrenal axis in sheep becomes functional during fetal life (Brooks et al 1992, McMillen et al 1995, Matthews & Challis 1996, Reperant & Durand 1997, Challis et al 2001. A steady increase in circulating concentrations of cortisol towards the end of gestation has an important role in the maturation of the fetal organ systems and in triggering parturition (Matthews & Challis 1996, Reperant & Durand 1997, Challis et al 2001.…”

Section: Introductionmentioning

confidence: 99%

A sex difference in the cortisol response to tail docking and ACTH develops between 1 and 8 weeks of age in lambs

Turner

Hosking²,

Parr³

et al. 2006

Journal of Endocrinology

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It is important to understand factors that may influence responses to stress, as these factors may also influence vulnerability to pathologies that can develop when stress responses are excessive or prolonged. It is clear that, in adults, the sex of an individual can influence the cortisol response to stress in a stressor specific manner. Nevertheless, the stage of development at which these sex differences emerge is unknown. We tested the hypothesis that there are sex differences in the cortisol response to tail docking and ACTH in lambs of 1 and 8 weeks of age. We also established cortisol responses in males when tail docking was imposed alone and in combination with castration at these ages. In experiment 1, 1 and 8 week old male and female lambs were subjected to sham handling, tail docking or, in males, a combination of tail docking and castration. In experiment 2, we administered ACTH (1·0 IU/kg) to male and female lambs at 1 and 8 weeks of age. There were significant cortisol responses to all treatments at both ages. Sex differences in the cortisol responses to tail docking and ACTH developed between 1 and 8 weeks of age, with females having greater responses than males. The data suggest that the mechanism for the sex difference in response to tail docking may involve the adrenal glands. At both ages, in males, the cortisol response to the combined treatment of tail docking and castration was significantly greater than that for tail docking alone.

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“…However, the short-lasting peak values around expulsion cannot be explained in this way. Maternal and foetal endocrine changes that lead to the onset of labour are well known and have been detailed in many papers (Barragry 1975, Cox 1975, McFeely & Ganjam 1976, Challis et al 1977, Flint et al 1978, Challis & Mitchell 1981, Brooks & Challis 1988, Thorburn et al 1991, Wood & Keller-Wood 1991, McMillen et al 1995. In sheep, an increase in the activity of the foetal hypothalamo-pituitary-adrenal axis initiates parturition (Liggins et al 1977).…”

Section: Figurementioning

confidence: 99%

Hormonal changes during parturition in heifers and goats are related to the phases and severity of labour

Hydbring¹,

Madej²,

MacDonald³

et al. 1999

Journal of Endocrinology

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Parturition is a natural event that involves stress and pain for the mother. We thus hypothesized that levels of stress hormones measured during parturition could reflect levels reached in response to severe discomfort and pain of other kinds as well. The aim of this study was therefore to determine whether plasma concentrations of cortisol, adrenaline, noradrenaline, -endorphin, met-enkephalin, vasopressin and oxytocin vary depending on the phase and severity of labour in dairy heifers (ten) and dairy goats (six), and how these hormones interact with each other. Blood samples were taken once a day for 3 days before labour and for 3 days afterwards and at predetermined phases during labour. All heifers delivered one calf and five of them needed obstetrical assistance. Two of the goats delivered one kid, and four had twins; all kidded without help. The cortisol concentration peaked when the calf and the first kid were born. In the heifers, plasma adrenaline increased after delivery, while the noradrenaline concentration did not change significantly in heifers that needed assistance, but increased during expulsion in heifers calving without help. In the goats, adrenaline and noradrenaline concentrations increased in association with expulsion of the first kid. The -endorphin concentration increased during labour in goats. In heifers that needed assistance, -endorphin concentration increased 1 h after labour but there was no change in heifers that did not need assistance. The met-enkephalin concentration was elevated during expulsion in heifers and fluctuated in the goats. Both oxytocin and vasopressin increased during expulsion in both groups of heifers, but vasopressin increased four times more in heifers needing assistance. In the goats, oxytocin reached its highest levels just as the feet of the first kid became visible, and vasopressin peaked as the head emerged. Parturition took longer in heifers that needed assistance than in those that did not. It is concluded that, even though the pattern of change differed between hormones during labour, the changes were related to the phases of labour. A longer labour therefore meant that the hormone concentrations stayed elevated for longer. Vasopressin reached high levels in goats and was the only hormone for which plasma concentrations were higher in heifers that needed assistance than in those that did not, indicating that this hormone is released in order to deal with the painrelated stress associated with labour.

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Chronic stress--the key to parturition?

Cited by 31 publications

References 28 publications

Chronic Maternal Fluoxetine Infusion in Pregnant Sheep: Effects on the Maternal and Fetal Hypothalamic-Pituitary-Adrenal Axes

Chronic Maternal Fluoxetine Infusion in Pregnant Sheep: Effects on the Maternal and Fetal Hypothalamic-Pituitary-Adrenal Axes

A sex difference in the cortisol response to tail docking and ACTH develops between 1 and 8 weeks of age in lambs

Hormonal changes during parturition in heifers and goats are related to the phases and severity of labour

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