Alterations in the hypothalamic pituitary adrenal axis during pregnancy and the placental clock that determines the length of parturition1
Section snippets
Placental secretion of corticotrophin releasing hormone
Corticotrophin releasing hormone (CRH) was first identified by Wylie Vale's group in 1981 (Vale et al., 1981). The peptide was localised to the hypothalamus and identified through its ability to stimulate ACTH released from the anterior pituitary. However, in 1982 CRH was identified within the human placenta and 2 years later high concentrations were reported in the plasma of women in the third trimester of pregnancy (Sasaki et al., 1987). Initial studies performed in our laboratory on extracts
The effect of placental CRH on the maternal pituitary
Early studies on CRH within the pregnant woman focused on whether the peptide would influence the maternal hypothalamic pituitary adrenal axis. Several groups have played a part in these investigations, including those of Robin Goland of Columbia Medical School in New York, Felice Petraglia from the University of Moderna, and several others. Our own studies demonstrated that a significant increase in plasma β-endorphin occurs as pregnancy advances but the increase, although statistically
Maternal CRH linkage to a biological clock determines the length of pregnancy
The dramatic increase in CRH concentrations in the pregnant woman's plasma during gestation prompted several groups to explore clinical correlates. Phil Lowry's group in Reading, UK, and their collaborators demonstrated that women in preterm labour had high concentrations of maternal plasma CRH compared to gestational aged matched controls (Wolfe et al., 1988). Similar results were reported by Robin Goland's group. At about the same time, Stalla's group in Germany reported that women with high
The action of placental CRH in both mother and fetus
How might CRH exert its actions to initiate parturition? CRH is secreted both into the maternal and the fetal circulations. In the maternal circulation CRH has potential access to the myometrium. CRH receptors have been identified within the myometrium and several groups have reported that CRH is able to potentiate the action of uterotonics (PGF2α and oxytocin) (Quartero et al., 1989, Benedetto et al., 1994). More recently Hillhouse's group in Warwick, UK, have demonstrated that late in
Regulation of placental CRH production
Glucocorticoids are not the only factors which have been shown to regulate CRH release, the gas nitric oxide has also been shown to have potent inhibitory actions on CRH release on syncytiotrophoblasts in vitro. Sun Kang of the Secondary Military Medical College, Shanghai, Peoples Republic of China, working within our own unit has demonstrated that sodium nitro-prusside inhibits CRH release from cultured placental cells and that this effect is mediated by inhibition of guanylate cyclase (Sun et
Animal models for studying placental CRH
Our more recent studies have focused on identifying a suitable animal model to explore the physiological roles of CRH during primate pregnancy. Our laboratory and that of Dr Golands have described the changes in CRH during baboon pregnancy and have found intriguing similarities and differences between baboons and humans (Smith et al., 1993). Whilst CRH production increases during the baboon pregnancy, it peaks during the second trimester and then falls in contrast to the pure exponential
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Amnion epithelial cell–derived exosomes induce inflammatory changes in uterine cells
2018, American Journal of Obstetrics and GynecologyCitation Excerpt :Endocrine signals arising from the fetus, such as corticotropin-releasing hormone and adrenocorticotropic hormone, are postulated to function as a biologic clock translating organ maturation and triggering labor at term. These hormones are known to have proinflammatory effects on various tissues in vitro.16–18 However, the precise mechanisms by which signals from the fetus initiate human parturition remain a mystery.
Chorioamniotic membrane senescence: A signal for parturition?
2015, American Journal of Obstetrics and GynecologyDiurnal cortisol patterns and psychiatric symptoms in pregnancy: Short-term longitudinal study
2014, Biological PsychologyCitation Excerpt :The lack of an expected increase in cortisol from the 2nd to 3rd trimester may also be explained by the higher risk status of the sample, which may have elevated second trimester diurnal cortisol values and reduced the likelihood of finding a gestational age effect. Furthermore, it is known that placental CRH increases with gestation, although the detection of a downstream increase in maternal salivary cortisol will be regulated by desensitization of pituitary CRH receptors (Schulte et al., 1990; Smith, 1998). Plasma CRH also increases with gestation and is elevated particularly in those who will deliver early (McLean et al., 1995; Wadhwa et al., 2004).
Preterm birth, fetal growth, and age at menarche among women exposed prenatally to diethylstilbestrol (DES)
2011, Reproductive ToxicologyCitation Excerpt :Another potential mechanism may be through a stress hormone pathway. Synthetic sources of estrogen may induce maternal and fetal stress, stimulating the secretion of corticotropin-releasing hormone (CRH) [33,34]. High concentrations of CRH concentrations have been associated with preterm labor and premature rupture of the membranes [35,36].
The Impact of Maternal Anemia on Perinatal Mortality: A Population-based, Prospective Cohort Study in China
2009, Annals of EpidemiologyCitation Excerpt :Hypoxia activates maternal and fetal stress responses through elevation of corticotrophin-releasing hormone or cortisol (18). This, in turn, results in restricted fetal growth (19) and preterm delivery (20). Iron deficiency may also increase oxidative stress resulting in damage to erythrocytes and the fetoplacental unit (18)—a mechanism that is commonly observed in studies of preeclampsia and gestational diabetes (21).
Are maternal cortisol levels related to preterm birth?
2009, JOGNN - Journal of Obstetric, Gynecologic, and Neonatal NursingCitation Excerpt :Compared with women with full-term birth, women with preterm birth have higher levels of CRH (Hobel et al.). These results suggest the presence of a “placental clock” for early delivery (Hobel et al.; McLean et al., 1995; Smith, 1998). One of the limitations of the studies included in the review is the repeated usage of a cross-sectional design.
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Paper presented at the workshop on Paracrine Mechanisms in Female Reproduction, Seville, Spain, June 1997.