THE EFFECTS OF DEXAMETHASONE AND INDOMETHACIN ON THE OUTCOME OF PREGNANCY IN THE RABBIT

1975 ◽  
Vol 64 (2) ◽  
pp. 363-370 ◽  
Author(s):  
J. R. G. CHALLIS ◽  
I. J. DAVIES ◽  
K. J. RYAN
Keyword(s):  
Late Pregnancy ◽  
Late Gestation ◽  
Premature Delivery ◽  
Progesterone Concentration ◽  
Dexamethasone Treatment ◽  
Similar Time ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Prostaglandin F ◽  
Length Of Gestation

SUMMARY Pregnant rabbits were treated with indomethacin (8–10 mg/kg/day) or dexamethasone (1·2–1·8 mg/kg/day) during late gestation. The effects of these treatments on the concentrations of progesterone and prostaglandin F (PGF) in the peripheral plasma, and the outcome of gestation were studied. Treatment with indomethacin significantly prolonged the length of gestation (P < 0·01) compared with control, untreated animals. In these treated animals, the plasma progesterone levels declined at a similar time to that in control rabbits but the increase in systemic PGF normally seen during late pregnancy was reduced. Dexamethasone treatment reliably induced premature delivery within 3–6 days. The plasma progesterone concentration fell rapidly during the first 24 h of dexamethasone administration, but in no animal was this associated with a significant increase in the plasma levels of PGF. These results are consistent with the suggestion that prostaglandins are involved in the normal initiation of parturition in the rabbit. They do not support the hypothesis that the effect of dexamethasone on the length of gestation is mediated through an increase in the production of prostaglandin F.

PERIPHERAL PLASMA PROGESTERONE CONCENTRATION OF COWS DURING PUBERTY, OESTROUS CYCLES, PREGNANCY AND LACTATION, AND THE EFFECTS OF UNDER-NUTRITION OR EXOGENOUS OXYTOCIN ON PROGESTERONE CONCENTRATION

1970 ◽  
Vol 48 (4) ◽  
pp. 599-614 ◽  
Author(s):  
L. E. DONALDSON ◽  
J. M. BASSETT ◽  
G. D. THORBURN
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Late Pregnancy ◽  
Ovarian Activity ◽  
Progesterone Concentration ◽  
Slow Increase ◽  
Normal Cycle ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Pregnancy And Lactation

SUMMARY Progesterone concentrations in the peripheral plasma of cows were measured by a protein-binding radioassay method. The mean concentration was lowest at oestrus (0·44 ng/ml) and then increased to a maximum of 6·8 ng/ml about day 14 of the 21-day cycle. The concentration decreased rapidly during the last 4 days of the cycle, reaching low levels on the day before oestrus. There were no significant changes in progesterone concentration during oestrus. After ovariectomy the plasma progesterone concentration decreased to a very low level (< 0·4 ng/ml). After hysterectomy, progesterone concentrations remained high for longer than in a normal cycle. At puberty, plasma progesterone concentrations indicated cyclic ovarian activity before the first observed oestrus. Daily treatment of cows with oxytocin (0·4 u./kg body weight) from day 2 reduced the oestrous cycle length to 9 days, but did not significantly alter the slow increase in plasma progesterone concentration during the first 5 days of the cycle. Plasma progesterone concentrations decreased again after day 5 to low values. Plasma progesterone concentration during early pregnancy was similar to the luteal phase value (4–6 ng/ml), declined during mid-pregnancy and then increased to a maximum (7–8 ng/ml) at about 240 days gestation. The concentration declined 2–3 weeks before calving. During lactation progesterone concentrations were very low until the resumption of cyclic ovarian activity. The first post-partum cycle, whether accompanied by observed oestrus or not, was usually preceded by a small increase in plasma progesterone concentration 3–5 days before the start of the cycle. Undernutrition significantly increased plasma progesterone concentrations in mid- and late pregnancy. Undernutrition of non-pregnant cows increased progesterone concentrations during the luteal phase of the first cycle, but reduced it in later cycles.

Concentrations of progesterone and oestradiol-17β after administration of a 3β-hydroxysteroid dehydrogenase inhibitor to sheep in late pregnancy

1987 ◽  
Vol 113 (1) ◽  
pp. 97-101 ◽  
Author(s):  
M. J. Taylor
Keyword(s):  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Hydroxysteroid Dehydrogenase ◽  
Premature Delivery ◽  
Plasma Progesterone ◽  
Twofold Increase ◽  
Rapid Fall

ABSTRACT An inhibitor of 3β-hydroxysteroid dehydrogenase (3β-HSD) activity was administered to sheep in late pregnancy. A rapid fall in plasma progesterone concentrations followed, associated with premature delivery by all animals 44±3 h (s.e.m.) after administration of inhibitor. A significant (about twofold) increase in plasma concentrations of oestradiol-17β was detected immediately before delivery. These results demonstrate, in contrast to previous reports, that 3β-HSD inhibitors have the capacity consistently to induce premature delivery associated with increased oestrogen release in sheep. J. Endocr. (1987) 113, 97–101

SEQUENTIAL CHANGES IN PLASMA PROGESTERONE IN THE COW DURING THE ESTROUS CYCLE, PREGNANCY, AT PARTURITION, AND POST-PARTUM

1972 ◽  
Vol 52 (4) ◽  
pp. 645-658 ◽  
Author(s):  
H. A. ROBERTSON
Keyword(s):  
Estrous Cycle ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Post Partum ◽  
Progesterone Concentration ◽  
Cyclic Activity ◽  
Gradual Decline ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Estrous Behavior

The progesterone concentration in peripheral plasma has been measured sequentially in individual cows during the estrous cycle, gestation, at parturition, and post-partum. During the estrous cycle the concentration was lowest just before, during, and just after estrus when the level (0.1–0.4 ng/ml) was similar to that found in three ovariectomized cows. The concentration commenced to rise on the 4th–6th day (day of estrus = 1st day), reached a peak of 3–6 ng/ml on the 11th–13th day, and dropped rapidly over a 24–48-hr period to a basal value 24–72 hr before the next estrus. In early pregnancy, the plasma progesterone concentration was similar to the maximum levels found during the luteal phase of the estrous cycle. Between 90 and 150 days there was an indication of a decline to a relatively low plasma progesterone concentration followed by a variable rise. Prior to parturition, there was a gradual decline over a period of 35–70 days reaching a level of <2.0 ng/ml the day before parturition. Following parturition, the level remained at <0.5 ng/ml until the first sign of the resumption of cyclic activity. The time for this to occur was very variable (20–>60 days). Although not conclusive, the evidence favors the view that for estrous behavior to occur, estrus must be preceded by luteal activity. The discharge of mucus can occur without previous luteal activity.

THE PROGESTERONE CONCENTRATION IN THE PLASMA OF THE GOAT DURING THE OESTROUS CYCLE AND PREGNANCY

1972 ◽  
Vol 52 (1) ◽  
pp. 23-36 ◽  
Author(s):  
G. D. THORBURN ◽  
W. SCHNEIDER
Keyword(s):  
Binding Assay ◽  
Progesterone Concentration ◽  
Maternal Circulation ◽  
Plasma Progesterone ◽  
Pregnant Uterus ◽  
Main Site ◽  
Peripheral Plasma ◽  
Protein Binding Assay ◽  
The Mean ◽  
Mean Concentration

SUMMARY Progesterone concentrations in the peripheral plasma of goats were measured by a protein-binding assay. The mean concentration was extremely low on the day of oestrus (0·2 ng/ml) and was not significantly different from that found in anoestrous or ovariectomized animals. The concentration increased to a maximum of 4 ng/ml on about day 10 of the 21-day cycle, and decreased rapidly during the last 3 days of the cycle. Plasma progesterone concentration during early pregnancy (2·5–3·5 ng/ml) was similar to the luteal phase value and remained steady from day 8 to day 60. Between days 60 and 70 there was a secondary increase in progesterone concentration which was maintained at this increased level (4·5–5·5 ng/ml) until just before parturition. In twin-bearing animals, the secondary increase was greater. Progesterone concentration decreased rapidly during the 1–2 days preceding parturition, but the concentration was still quite high on the day of parturition (1·25 ng/ml). The progesterone concentration in peripheral plasma was markedly increased during anaesthesia and the operation. After bilateral ovariectomy of the pregnant goat, peripheral progesterone concentration fell rapidly from 9 to 2·5 ng/ml during the first ½ h and then more slowly during the next 5–6 h. The animals aborted 36–48 h later. A consistent positive arterio—venous difference for progesterone was observed across the pregnant uterus in two unanaesthetized goats. These results indicate that the ovary is the main site of progesterone production in the pregnant goat and that production by the placenta is small and unlikely to influence the level of this hormone in the maternal circulation.

523. PLACENTAL ANTIOXIDANT ENZYMES IN RAT PREGNANCY SHOW ZONE- AND STAGE-DEPENDENT VARIATION

2009 ◽  
Vol 21 (9) ◽  
pp. 122
Author(s):  
M. L. Jones ◽  
P. J. Mark ◽  
T. A. Mori ◽  
B. J. Waddell
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Enzymes ◽  
Oxidative Damage ◽  
Mrna Expression ◽  
Late Pregnancy ◽  
Late Gestation ◽  
Ros Generation ◽  
Dexamethasone Treatment ◽  
Endogenous Protection ◽  
Thioredoxin Reductases

Placental oxidative stress plays a key role in the pathophysiology of placenta-related disorders including preeclampsia. Protection from oxidative stress is provided by antioxidant enzymes which inactivate reactive oxygen species (ROS). The rat placenta consists of two major zones, the junctional (JZ) and labyrinth (LZ), and because only the LZ grows in late gestation we hypothesized it generates more ROS and thus requires greater antioxidant protection. Our previous studies on expression of the antioxidants superoxide dismutase (SOD)-1, SOD-2 and catalase support this hypothesis. Here, we extend these observations to include mRNA expression of SOD-3 and thioredoxin reductases (Txnrd-1, -2, -3) and activities of SOD, hydrogen peroxide (H2O2) scavenging and xanthine oxidase (XO). Placental oxidative damage was assessed by measurement of F2-isoprostanes and TBARS concentrations. We also measured the effects of maternal dexamethasone treatment, since glucocorticoid excess is known to induce oxidative damage in other tissues. Placentas were collected from untreated mothers on days 16 and 22 (term=day 23) and on day 22 after dexamethasone treatment from day 13 (1 μg/ml drinking water). SOD-3, Txnrd-1, -2, and -3 mRNAs were measured in JZ and LZ by qRT-PCR. F2-isoprostanes were measured by GC-MS and kit assays were used to measure TBARS and the activities of SOD, H2O2 scavenging and XO. In both placental zones, expression of SOD-3 and Txnrd-1 mRNAs and H2O2 scavenging activity decreased from day 16 to 22, whereas XO activity increased. Dexamethasone treatment increased H2O2 scavenging in both zones, but had no effect on SOD or XO activities or antioxidant mRNA expression. Despite predicted increases in placental ROS generation in late pregnancy and after dexamethasone, neither F2-isoprostanes nor TBARS were increased. These and our previous data suggest that endogenous protection against oxidative stress is abundant in the rat placenta and provides protection against potential oxidative insults including glucocorticoid excess.

EFFECT OF PROGESTERONE WITHDRAWAL IN SHEEP DURING LATE PREGNANCY

1982 ◽  
Vol 92 (1) ◽  
pp. 85-93 ◽  
Author(s):  
M. J. TAYLOR ◽  
R. WEBB ◽  
M. D. MITCHELL ◽  
J. S. ROBINSON
Keyword(s):  
Dehydrogenase Activity ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Hydroxysteroid Dehydrogenase ◽  
Peripheral Plasma ◽  
Activity Concentrations ◽  
Pregnant Sheep ◽  
Prostaglandin F

The concentration of progesterone in the peripheral plasma of seven sheep during late pregnancy was reduced by injection of an inhibitor of 3β-hydroxysteroid dehydrogenase activity. Concentrations of progesterone were 10·0± 1·0(s.e.m.) ng/ml (n = 6) before injection of the inhibitor, fell to 1·39 ± 0·40 ng/ml (n = 6) 30 min after injection, and remained within this lowered range for 6 h after injection. By 20–24 h and 30–35 h after injection progesterone concentrations had recovered to 4·63±0·94 and 14·07 ±4·17 ng/ml respectively (n = 6). Six out of seven ewes delivered prematurely 32·5± 2·9 h after injection. Delivery appeared to be normal, and was associated with increasing concentrations of 13,14-dihydro-15-oxo prostaglandin F2α in peripheral plasma. Concentrations of oestradiol-17β17β in peripheral plasma were slightly raised immediately before delivery, at which time progesterone concentrations were within the preinjection range. These data suggest that progesterone withdrawal is one mechanism that initiates increased prostaglandin F2α secretion in the pregnant sheep.

Increasing feed intake in late gestation does not affect plasma progesterone concentration in the sow

2004 ◽  
Vol 62 (9) ◽  
pp. 1618-1626 ◽  
Author(s):  
Helen Margaret Miller ◽  
George Robert Foxcroft ◽  
Frank Xavier Aherne
Keyword(s):  
Feed Intake ◽  
Late Gestation ◽  
Progesterone Concentration ◽  
Plasma Progesterone

THE CONCENTRATION OF PROGESTERONE IN THE PERIPHERAL PLASMA OF THE PREGNANT EWE

1969 ◽  
Vol 45 (3) ◽  
pp. 449-457 ◽  
Author(s):  
J. M. BASSETT ◽  
TANA J. OXBORROW ◽  
I. D. SMITH ◽  
G. D. THORBURN
Keyword(s):  
Protein Binding ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
High Concentrations ◽  
Pregnant Ewe

SUMMARY The progesterone concentration in the peripheral plasma of ewes throughout pregnancy has been determined by a protein-binding method. Plasma progesterone concentrations during the first 50 days of pregnancy (2–3 ng./ml.) were not significantly higher than peak concentrations during the luteal phase in cycling non-pregnant ewes, but there was no decrease in the concentration 15–20 days after mating as occurs in non-pregnant ewes. Between 50 and 120 days after mating the plasma progesterone concentration increased steadily to values 2–5 times that found in early pregnancy. These high concentrations were maintained until lambing. A decrease in progesterone concentration during the week preceding lambing was usually, but not always, observed. Mean plasma progesterone concentrations during the last 50 days of pregnancy in ewes with twins were approximately twice those in ewes with a single foetus.

FOETAL AND MATERNAL PLASMA CONCENTRATIONS OF 13,14-DIHYDRO-15-OXO-PROSTAGLANDIN F IN THE MARE DURING LATE PREGNANCY AND AT PARTURITION

1978 ◽  
Vol 78 (2) ◽  
pp. 201-215 ◽  
Author(s):  
R. J. BARNES ◽  
R. S. COMLINE ◽  
L. B. JEFFCOTT ◽  
M. D. MITCHELL ◽  
P. D. ROSSDALE ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Maximum Concentration ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Maternal Plasma ◽  
Premature Delivery ◽  
Rapid Rise ◽  
Second Stage ◽  
Prostaglandin F ◽  
Venous Plasma

SUMMARY The concentrations of 13,14-dihydro-15-oxo-prostaglandin F (PGFM), the stable metabolite of prostaglandin F, were measured in the plasma of catheterized mares and foetuses and non-catheterized thoroughbred mares and ponies during the last months of gestation. The plasma concentration of PGFM increased gradually towards term in all groups of animals. During the operation for insertion of catheters, maternal and foetal concentrations of PGFM were high, but the values fell to basal levels 24–48 h after the operation. It was found that preoperative starvation (24 h) led to a rise in the concentration oef PGFM in th maternal plasma. The raised concentrations of PGFM during the operation were associated with low progestogen and high oestrogen concentrations in umbilical venous plasma. The subsequent survival period of the catheterized foal was inversely related to the maximum concentration of PGFM attained during the operation. Changes in the plasma concentration of PGFM were studied during normal parturition in thoroughbred mares, during oxytocin-induced delivery in non-catheterized ponies and during premature delivery or abortion in the catheterized animals. The greatest increase in the concentration of PGFM was seen in the thoroughbred animals during second-stage labour; oxytocin also resulted in a very rapid rise in the level of PGFM, which remained high until delivery. In the catheterized animals, the birth of live foetuses was associated with a rise in the concentration of PGFM in both foetal and maternal plasma during the last 2 h before delivery. Less consistent changes were found during abortion.

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