Parturition in the Goat: Plasma Concentrations of Prostaglandin F and Steroid Hormones and Uterine Activity During Late Pregnancy and Parturition

Umo, I.; Fitzpatrick, R. J.; Ward, W. R.

doi:10.1677/joe.0.0680383

Cited by 46 publications

(23 citation statements)

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“…We therefore assume that the large changes observed in arterial progesterone concentrations broadly reflect changes in luteal function. Our finding of a decrease in systemic progesterone concentrations beginning some days before labor is consistent with some previous studies [31,38,41,42] and at variance with others that found a precipitous decrease in the last 24 h before parturition [4,9,43]. On balance, we believe that the present results indicate that the signal for luteolysis is given some days before labor and that the final, precipitous fall in progesterone concentrations during the last day before delivery is the consequence of labor-associated PGF 2 .…”

Section: Discussionsupporting

confidence: 93%

“…Prostaglandin concentrations measured in the UOV and carotid artery in this study are in close agreement with prostaglandin concentrations measured in other studies involving goats [4,41,43]. PGE concentrations in the UOV exceeded those in the arterial circulation, consistent with previous suggestions that the uterus is the major source of prostaglandin production in late gestation [34].…”

Section: Discussionsupporting

confidence: 92%

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Fetal and Maternal Endocrine Changes Approaching Parturition in the Goat: Lack of Evidence for Prostaglandins E2 and F2α as Signals for Luteolysis1

Ford

Young

Caddy

et al. 1998

Biology of Reproduction

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We investigated the temporal relationship of fetal cortisol secretion to circulating concentrations of fetal ACTH1-39 and its high-molecular weight precursors in goats. We also measured the concentrations of progesterone, estradiol-17beta estrone sulfate, prostaglandin (PG) E, PGF2alpha, and PGF2alpha metabolite (PGFM) in maternal arterial plasma over the last month of gestation. Prostaglandin concentrations were also measured in utero-ovarian venous plasma. There was a positive association between ACTH1-39 in fetal plasma and the prepartum surge in fetal cortisol that commenced 8 days before labor. The fetal cortisol surge was followed by a simultaneous decrease in maternal progesterone and an increase in plasma estrogens commencing 3-4 days before labor. No change in basal prostaglandin concentration occurred before this time. There was a positive veno-arterial difference of PGE and PGF2alpha across the uterine vascular bed, confirming the uteroplacental unit as a major source of these eicosanoids in the plasma of the pregnant doe. We conclude that the fetal signal for parturition precedes luteolysis by some 5 days and find no evidence of changes in the basal concentrations of PGE and PGF2alpha in maternal plasma at the time of luteolysis.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 92%

Fetal and Maternal Endocrine Changes Approaching Parturition in the Goat: Lack of Evidence for Prostaglandins E2 and F2α as Signals for Luteolysis1

Ford

Young

Caddy

et al. 1998

Biology of Reproduction

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“…In the present study, as in some others, luteolysis appeared to occur in two stages [6,8,14,15]. Mean arterial plasma progesterone concentrations declined a week before labor, and a second, more abrupt decrease in circulating progesterone occurred on the day of labor.…”

Section: Discussionsupporting

confidence: 82%

“…Luteal maintenance in this species depends, in turn, on the balance between luteotrophic and luteolytic factors [1,2]. Luteolysis in the pregnant doe at term is believed to be due to the secretion of a luteolysin, prostaglandin (PG)F 2␣ , from the uterus, since this compound is the luteolysin of the estrous cycle and is secreted into the utero-ovarian vein (UOV) in large quantities during the last 24 h before parturition [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Pulsatile Output of Prostaglandin F2α Does Not Increase Around the Time of Luteolysis in the Pregnant Goat1

Ford

Thorburn

Caddy

et al. 1999

Biology of Reproduction

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Prostaglandin (PG) F(2alpha) secreted from the uterus is the luteolysin of the estrous cycle and is also believed to be responsible for luteolysis in the pregnant doe at term. We have reported that basal progesterone concentrations decrease before basal PGF(2alpha) concentrations increase, which is inconsistent with this view. In this study we investigated whether luteolysis is associated with increased frequency or amplitude of pulsatile PGF(2alpha) secretion in does over the last 2 wk of gestation. Progesterone concentrations decreased approximately 1 wk before parturition. There was no accompanying increase in PGF(2alpha) concentrations or pulse frequency, and those pulses that were observed were of lesser amplitude and duration than those that have been associated with luteolysis in cycling ewes. A small increase in PGF(2alpha) pulse frequency was identified during the 3 days before parturition, but this was not associated with any change in progesterone concentrations. The biological significance of these small changes in PGF(2alpha) pulse frequency is obscure, although the high concentration of this eicosanoid at labor may have been related to the final, precipitous decline in plasma progesterone concentrations. These findings do not support the notion that PGF(2alpha) is the principal luteolysin in the pregnant doe at term.

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“…Various workers have reported oestrogen concentrations in goat plasma in late pregnancy and at parturition (Thorburn, Nicol, Basse«, Shutt & Cox, 1972;Currie, Wong, Cox & Thorburn, 1973;Umo, Fitzpatrick & Ward, 1976;Flint, Kingston, Robinson & Thorburn, 1978). Although Challis & Linzell( 1971) described total unconjugated oestrogens at various stages of pregnancy in the goat, little is known about individual oestrogen concentrations at these stages.…”

Section: Introductionmentioning

confidence: 99%

Oestrogen concentrations in systemic plasma of pregnant pygmy goats

Dhindsa¹,

Metcalfe²,

Resko³

1981

Reproduction

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Concentrations of oestradiol-17 beta, oestradiol-17 alpha, and oestrone in systemic plasma of pregnant pygmy goats (Capra hircus) remained low until about Day 60 and then rose to maximum values at Days 120-140 (parturition Day 140-145). Oestradiol-17 alpha was the predominant oestrogen. All 3 oestrogens at Days 100-130 were higher in females carrying 3 fetuses than in those carrying only one, but at Days 70-90 only oestrone values were higher. It is suggested that the feto-placental unit is the source of oestrogens during gestation in goats.

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Parturition in the Goat: Plasma Concentrations of Prostaglandin F and Steroid Hormones and Uterine Activity During Late Pregnancy and Parturition

Cited by 46 publications

References 0 publications

Fetal and Maternal Endocrine Changes Approaching Parturition in the Goat: Lack of Evidence for Prostaglandins E2 and F2α as Signals for Luteolysis1

Fetal and Maternal Endocrine Changes Approaching Parturition in the Goat: Lack of Evidence for Prostaglandins E2 and F2α as Signals for Luteolysis1

Pulsatile Output of Prostaglandin F2α Does Not Increase Around the Time of Luteolysis in the Pregnant Goat1

Oestrogen concentrations in systemic plasma of pregnant pygmy goats

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