Prolonged Gestation in Ewes After Foetal Adrenalectomy

Drost, Maarten R.; Holm, L. W.

doi:10.1677/joe.0.0400293

Cited by 105 publications

(41 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Obst and Seamark (1975) reported an association between the length of parturition and the concentration of plasma corticosteroids in the 8-h period before birth. Obst (1971) postulated that a high concentration of maternal corticosteroids may inhibit the development of the foetal pituitary-adrenal axis necessary for successful parturition (Liggins et al 1967;Drost and Holm 1968). There was no evidence in our study that the difference in corticosteroid concentrations between HbA and HbB ewes affected lambing.…”

Section: Discussioncontrasting

confidence: 70%

Influence of Haemoglobin Type and Selenium Status on Peripheral Plasma Progesterone and Corticosteroid Concentration in Ewes Grazing Oestrogenic Pastures

Walker¹,

Obst²,

Smith³

et al. 1979

Aust. Jnl. Of Bio. Sci.

View full text Add to dashboard Cite

Peripheral plasma progesterone and corticosteroid concentrations were studied in ewes grazing oestrogenic pastures during oestrus, pregnancy and parturition in 1974 and during pregnancy in 1975. Haemoglobin (Hb) type A ewes had significantly higher mean corticosteroid concentrations than HbB ewes in both years. In 1974 the concentration of progesterone did not differ significantly between Hb types whilst in 1975 the concentration was significantly (P < 0·001) higher in HbA ewes.The mean corticosteroid concentrations were higher in selenium-supplemented ewes of both Hb types than in unsupplemented ewes in 1974 but lower in 1975. Selenium treatment did not significantly influence the progesterone concentration in ewes of both Hb types in 1974 but significantly (P< 0'01) increased it in 1975.It is concluded that the higher concentration of plasma corticosteroids or factors regulating the relationship between corticosteroids and progesterone could be responsible for the higher estimates of embryonic mortality reported in HbA ewes.

show abstract

Section: Discussioncontrasting

confidence: 70%

Influence of Haemoglobin Type and Selenium Status on Peripheral Plasma Progesterone and Corticosteroid Concentration in Ewes Grazing Oestrogenic Pastures

Walker¹,

Obst²,

Smith³

et al. 1979

Aust. Jnl. Of Bio. Sci.

View full text Add to dashboard Cite

show abstract

“…It is clear that an intact hypothalamopituitary-adrenal (HPA) axis is critical for the normal cortisol surge and parturition, as disruption at any level of the axis results in decreased cortisol concentrations and a failure of parturition (Liggins et al 1967, Drost & Holm 1968, Antolovich et al 1991, Myers et al 1993. Furthermore, the infusion of pituitary adrenocorticotrophin (ACTH 1-24 ) or adrenal (cortisol) hormones of the HPA axis induces premature labour in intact fetuses, and restores cortisol concentrations and parturition in fetuses that have had lesions of these respective organs (Liggins & Thorburn 1994, Poore et al 1998.…”

Section: Introductionmentioning

confidence: 99%

The role of the pituitary gland and ACTH in the regulation of mRNAs encoding proteins essential for adrenal steroidogenesis in the late-gestation ovine fetus

Simmonds¹,

Phillips²,

Poore³

et al. 2001

Journal of Endocrinology

View full text Add to dashboard Cite

To further understand the relative roles of the pituitary gland and ACTH in the regulation of mRNAs encoding proteins that are essential for adrenal development, we investigated the effects of, first, an ACTH infusion and labour in intact fetuses and, secondly, the effect of an ACTH infusion to fetuses with and without a pituitary gland, on the relative abundance of the mRNA encoding for the ACTH receptor (MC2R), steroidogenic factor 1 (SF-1), cholesterol side-chain cleavage enzyme (P450 scc ), 3 -hydroxysteroid dehydrogenase (3 HSD) and 17 -hydroxylase (P450 C17 ) in the fetal adrenal gland. ACTH 1-24 infusion (14·7 pmol/kg per h) to intact fetuses was without effect on the abundance of mRNA encoding MC2R and SF-1, irrespective of whether the infusion was given for 18 (115-132 days of gestation) or 32 days (115 days to term (147 days of gestation)). Hypophysectomy (HX) did not alter the expression of MC2R mRNA; however, the abundance of SF-1 mRNA fell by approximately 50% following the removal of the pituitary gland. ACTH 1-24 infusion to HX fetuses failed to restore levels of SF-1 mRNA to that seen in intact animals. P450 scc and 3 HSD mRNAs were increased by ACTH 1-24 infusion for 18 days in intact animals, although no effects of the infusion were seen on P450 C17 mRNA levels. For all three of these mRNAs, there was a significant increase in their abundance between 132 days of gestation and term in intact fetuses. By term, ACTH 1-24 infusion was without any additional effect on their abundance. HX decreased the expression of P450 scc , 3 HSD and P450 C17 mRNAs, while ACTH 1-24 infusion to HX fetuses increased the expression of these mRNAs to levels seen in intact animals. There were significant correlations between the abundance of the mRNA for P450 scc , 3 HSD and P450 C17 , but not MC2R and SF-1, and premortem plasma cortisol concentrations. These results emphasise the importance of the pituitary gland and ACTH in the regulation of the enzymes involved in adrenal steroidogenesis. Factors in addition to ACTH may also play some role, as the infusion was not always effective in increasing the abundance of the mRNAs. Surprisingly, the mRNA for MC2R and SF-1 did not appear to be regulated by ACTH in the late-gestation ovine fetus, though a pituitary-dependent factor may be involved in the regulation of SF-1 mRNA abundance.

show abstract

“…Chez la Brebis, il est établi que la fonction hypophyso surrénalienne du foetus détermine et contrôle le mécanisme de la naissance (Liggins et ai., 1967 ;Drost et Holm, 1968 ;Liggins, 1968). Ainsi, la perfusion du foetus par un corticostéroïde de synthèse (la dexaméthasone) est suivie de la mise-bas prématurée (Liggins et al,1973 ;Currie et al, 1973) et l'administration du même produit à la mère peut induire l'agnetage (Bosc, 1970 (Bosc, 1972 ;Bosc et Fèvre, 1974 (Challis et al, 1972 ;Thorburn et al, 1972 ;Liggins et al, 1973 ;Robertson et Smeaton, 1973).…”

Section: Introductionunclassified

Motricité utérine de la Brebis, avant, pendant et après la parturition spontanée ou après traitement par la dexaméthasone

Prud'homme¹,

Bosc²,

Nicolle³

et al. 1977

Ann. Biol. anim. Bioch. Biophys.

View full text Add to dashboard Cite

show abstract

Prolonged Gestation in Ewes After Foetal Adrenalectomy

Cited by 105 publications

References 2 publications

Influence of Haemoglobin Type and Selenium Status on Peripheral Plasma Progesterone and Corticosteroid Concentration in Ewes Grazing Oestrogenic Pastures

Influence of Haemoglobin Type and Selenium Status on Peripheral Plasma Progesterone and Corticosteroid Concentration in Ewes Grazing Oestrogenic Pastures

The role of the pituitary gland and ACTH in the regulation of mRNAs encoding proteins essential for adrenal steroidogenesis in the late-gestation ovine fetus

Motricité utérine de la Brebis, avant, pendant et après la parturition spontanée ou après traitement par la dexaméthasone

Contact Info

Product

Resources

About