Biosynthesis and possible biological roles of progestagens during equine pregnancy and in the newborn foal

Chavatte, Pascale; Holtan, D. W.; Ousey, Jennifer C.; Rossdale, P. D.

doi:10.1111/j.2042-3306.1997.tb05084.x

Cited by 38 publications

(30 citation statements)

References 36 publications

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“…synthesize significant quantities of pregnenolone. Chavatte et al [137,138] found that adrenals from mid-to-late gestation fetuses exhibited little or no capacity to use cholesterol for steroid synthesis when compared with adrenal tissue from foals, concluding that "the 5a-pregnanes found in fetal blood in late gestation do not originate from the adrenal" [138]. Han et al [139] noted relatively few cells in the equine fetal adrenal cortex expressing cytochrome P450 cholesterol side-chain cleavage, the enzyme directly responsible for pregnenolone synthesis.…”

Section: The Feto-placental Unitmentioning

confidence: 95%

Review of the reproductive endocrinology of the pregnant and parturient mare

Conley

2016

Theriogenology

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Section: The Feto-placental Unitmentioning

confidence: 95%

Review of the reproductive endocrinology of the pregnant and parturient mare

Conley

2016

Theriogenology

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“…The fetal HPA axis may have a role in controlling the length of gestation in the mare through adrenal production of pregnenolone, P 5 (Silver 1994; Chavatte et al . 1997; Ousey 2004; Fowden et al .…”

Section: The Hypothalmic‐pituitary‐adrenal Axismentioning

confidence: 99%

“…2008). This steroid is believed to be the main precursor for uteroplacental production of the progestagens that control uterine quiescence during the second half of equine pregnancy (Silver 1994; Chavatte et al . 1997; Ousey et al .…”

Section: The Hypothalmic‐pituitary‐adrenal Axismentioning

confidence: 99%

Endocrine adaptations in the foal over the perinatal period

Fowden

Forhead

Ousey

2012

Equine Veterinary Journal

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SummaryIn adapting to life ex utero, the foal encounters a number of physiological challenges. It has to assume the nutritional, respiratory and excretory functions of the placenta and activate full regulatory control over its own internal environment for the first time. To achieve this, there must be structural and functional changes to a wide range of tissues including several endocrine glands. In most species, including the horse, these maturational changes begin in late gestation and continue into the first few days of neonatal life. Consequently, during this perinatal period, there are major changes in the sensitivity and/or set point of key endocrine axes, which alter the circulating hormone concentrations in the foal. In turn, these endocrine changes are responsible for many of the other physiological adaptations essential for neonatal survival. The perinatal alterations in the hypothalamic-pituitary-adrenal (HPA) axis are particularly important in these processes, although the sympatho-adrenal medullary axis and endocrine pancreas also have key roles in ensuring homeostasis during the multiple novel stimuli experienced at birth. Abnormalities in the perinatal endocrine profile caused by adverse conditions before or after birth may, therefore, lead to maladaptation or aid survival of the newborn foal depending on the specific circumstances. This review examines the perinatal changes in endocrinology in normal and compromised foals and the role of these endocrine changes in the physiological adaptations to extrauterine life with particular emphasis on the HPA axis, adreno-medullary catecholamines and the endocrine pancreas.

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“…Most 5 α‐DHP is then returned to the foetus and further metabolized into other progestins, while some (30%) is excreted into the maternal circulation along with other progestins (Hamon et al. 1991; Chavatte et al. 1997; Ousey et al.…”

Section: Endocrinologymentioning

confidence: 99%

Ascending Placentitis in the Mare: An Update

LeBlanc

2010

Reprod Domestic Animals

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Contents Ascending placentitis is a common cause of premature birth, abortion and delivery of compromised, ill foals. Recent experimental models have investigated diagnostic procedures and treatment strategies in an attempt to improve live foal rate. Diagnostics such as transrectal and transabdominal ultrasonography are used to evaluate foetal well‐being and placental separation, while measurement of plasma progestins or oestrogen identifies a stressed or hypoxic foetus. Treatment is directed at stopping spread of infection, maintaining uterine quiescence and blocking production of pro‐inflammatory cytokines. It must be instituted early if a pregnancy is to be saved. Treatments include antibiotics, tocolytics and immunomodulators. Prompt, aggressive treatment with antibiotics has improved foal viability in experimental models of placentitis.

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Biosynthesis and possible biological roles of progestagens during equine pregnancy and in the newborn foal

Cited by 38 publications

References 36 publications

Review of the reproductive endocrinology of the pregnant and parturient mare

Review of the reproductive endocrinology of the pregnant and parturient mare

Endocrine adaptations in the foal over the perinatal period

Ascending Placentitis in the Mare: An Update

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