β-Endorphin in sows during late pregnancy: effects of cloprostenol and oxytocin on plasma concentrations of β-endorphin in the jugular and uterine veins

1993 ◽  
Vol 136 (2) ◽  
pp. 199-206 ◽  
Author(s):  
J. E. Aurich ◽  
I. Dobrinski ◽  
N. Parvizi
Keyword(s):  
Opioid Peptides ◽  
Surgical Intervention ◽  
Physiological Function ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Oestrous Cycle ◽  
Maternal Circulation ◽  
Peripheral Plasma ◽  
Prostaglandin F

ABSTRACT β-Endorphin was measured in the plasma of pigs during late pregnancy and at different stages of the oestrous cycle. In pregnant animals, β-endorphin secretion from uteroplacental tissues into the maternal circulation and the possible effects of oxytocin and the prostaglandin F2α (PGF2α) analogue cloprostenol on β-endorphin release were determined. Plasma β-endorphin concentrations in pregnant sows were significantly higher than in non-pregnant pigs. However, there were no significant changes in β-endorphin values throughout the oestrous cycle. Because the increase in plasma β-endorphin concentrations had occurred before luteolysis and onset of labour it could not be attributed to the stress of parturition. The surgical intervention of a laparotomy increased β-endorphin release into peripheral plasma. Cloprostenol but not oxytocin caused an immediate increase in plasma β-endorphin concentrations. At parturition, endogenous PGF2α may be involved in the regulation of β-endorphin secretion. Concentrations of β-endorphin in the jugular and uterine vein plasma were not significantly different, and so it would appear that β-endorphin in the plasma of pregnant sows is not of uteroplacental origin. In conclusion, changes in the concentration of β-endorphin in peripheral plasma, associated with pregnancy but not the oestrous cycle, exist in pigs. Hence a physiological function of peripheral opioid peptides in the periparturient sow is feasible. Journal of Endocrinology (1993) 136, 199–206

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.

Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus)

Reproduction ◽  
2000 ◽  
pp. 49-57 ◽  
Author(s):  
SD Johnston ◽  
MR McGowan ◽  
P O'Callaghan ◽  
R Cox ◽  
V Nicolson
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Plasma Concentrations ◽  
External Genitalia ◽  
Oestrous Cycle ◽  
Phascolarctos Cinereus ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
The Mean ◽  
High Concentrations

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

Cyclical changes in the uterine endometrium and peripheral plasma concentrations of progesterone in the marsupial Trichosurus vulepcula

1973 ◽  
Vol 21 (1) ◽  
pp. 1 ◽  
Author(s):  
CD Shorey ◽  
RL Hughes
Keyword(s):  
Blood Plasma ◽  
Peripheral Blood ◽  
Plasma Concentrations ◽  
Secretory Activity ◽  
Oestrous Cycle ◽  
Uterine Endometrium ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
Functional Differences ◽  
Peripheral Blood Plasma

The proliferation and secretory activity of the uterine endometrium in the marsupial T. vulpecula is examined at the cellular and subcellular levels throughout the 26-day oestrous cycle. The observations described are correlated with measured concentrations of progesterone in the peripheral blood plasma. Evidence cited indicates that there are no significant functional differences in the uterine endometrial secretory activity during the 17.5-day gestation period in pregnant females, compared with those in a normal oestrous cycle. Progesterone assays carried out on blood plasma taken from 20 staged animals throughout the oestrous cycle, five of which were at known stages of gestation, also supports the view that pregnancy does not significantly alter the physiological pattern of the reproductive cycle in this marsupial.

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.

Peripheral plasma concentrations of pregnenolone sulphate, pregnenolone, progesterone and 20α-hydroxy-4-pregnen-3-one in ewes throughout the oestrous cycle

1987 ◽  
Vol 113 (2) ◽  
pp. 231-237 ◽  
Author(s):  
S. A. McKay ◽  
G. Jenkin ◽  
G. D. Thorburn
Keyword(s):  
Plasma Concentration ◽  
Corpus Luteum ◽  
Plasma Concentrations ◽  
Oestrous Cycle ◽  
Positive Correlation ◽  
Peripheral Plasma

ABSTRACT Pregnenolone sulphate, pregnenolone, progesterone and 20α-hydroxy-4-pregnen-3-one concentrations in peripheral plasma of normal cyclic ewes were measured by radioimmunoassay. The concentrations of these steroids were correlated with that of progesterone. The concentrations of all the steroids measured in peripheral plasma varied in a cyclic manner and showed a significant (P <0·05) positive correlation with the concentration of progesterone. Peripheral plasma concentrations of these steroids in ovariectomized and ovariectomized, dexamethasone-treated ewes were also determined. The plasma concentration of progesterone in ovariectomized ewes was undetectable but the concentrations of pregnenolone sulphate, pregnenolone and 20α-hydroxy-4-pregnen-3-one remained similar to those observed at oestrus. Administration of dexamethasone to ovariectomized ewes had no effect on pregnenolone sulphate or pregnenolone concentrations but 20α-hydroxy-4-pregnen-3-one concentrations, which were already very low, decreased further. It is proposed that the ovary, probably the corpus luteum, secretes pregnenolone sulphate, pregnenolone and 20α-hydroxy-4-pregnen-3-one; however, pregnenolone sulphate and 20α-hydroxy-4-pregnen-3-one may also arise from the metabolism of circulating pregnenolone and progesterone. J. Endocr. (1987) 113, 231–237.

Peripheral plasma progesterone concentrations in pregnant and non-pregnant greyheaded flying-foxes (Pteropus poliocephalus) and little red flying-foxes (P. scapulatus)

1995 ◽  
Vol 7 (5) ◽  
pp. 1163 ◽  
Author(s):  
PA Towers ◽  
L Martin
Keyword(s):  
Breeding Season ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Corpora Lutea ◽  
Flying Foxes ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Pteropus Poliocephalus ◽  
In The Wild ◽  
Gas Chromatography Mass Spectroscopy

Blood was collected from breeding-season and pregnant P. poliocephalus females shot in the wild and from captive pregnant and ovariectomized P. poliocephalus and P. scapulatus females. Peripheral plasma progesterone concentrations measured by radioimmunoassay were similar to those obtained by gas chromatography-mass spectroscopy: in intact non-pregnant P. poliocephalus females without corpora lutea (CLs) values ranged from 2 to 30 ng mL-1; after ovariectomy, they ranged from 1 to 85 ng mL-1. A significant source of progesterone in these bats may be the adrenal. In P. poliocephalus, peripheral plasma progesterone concentrations showed relatively little change over the breeding season or in early pregnancy when a CL formed, but increased from mid pregnancy to reach 200-800 ng mL-1 in late pregnancy. A mid-pregnancy ovary with CL contained 2.80 ng progesterone whereas the contralateral ovary contained 0.13 ng. Overall, CL size decreased during pregnancy and was negatively correlated with plasma progesterone concentrations. In late pregnancy, the main source of progesterone appears to be the placenta; plasma concentrations increase with placental growth and are significantly correlated with placental weight, and placentas contain 4-8 micrograms progesterone g-1. There was no evidence that progesterone concentrations fall before parturition. Limited observations indicated that peripheral progesterone concentrations follow similar patterns in P. scapulatus.

PARTURITION IN THE GOAT: PLASMA CONCENTRATIONS OF PROSTAGLANDIN F AND STEROID HORMONES AND UTERINE ACTIVITY DURING LATE PREGNANCY AND PARTURITION

1976 ◽  
Vol 68 (3) ◽  
pp. 383-389 ◽  
Author(s):  
I. UMO ◽  
R. J. FITZPATRICK ◽  
W. R. WARD
Keyword(s):  
Steroid Hormones ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Experimental Period ◽  
Significant Decline ◽  
Progesterone Concentration ◽  
Uterine Activity ◽  
Uterine Contractions ◽  
Prostaglandin F

SUMMARY Changes in plasma concentrations of hormones and uterine activity associated with spontaneous parturition in the goat were examined. No change in oestradiol-17β concentration was detected during the experimental period, but oestradiol-17α consistently increased in concentration 3–4 days before parturition. This was followed by an increase in prostaglandin F two days later, while a pre-partum decline in progesterone concentration occurred 18–20 h after the significant increase in prostaglandin F. The onset of uterine contractions coincided with a significant decline in progesterone concentration and a period of continually rising prostaglandin F and oestradiol-17α concentrations. Uterine activity expressed in Montevideo units did not change until 10–8 h before foetal expulsion. These results support the hypothesis that in the goat the elevated prepartum concentration of prostaglandin F brings about luteolysis and a subsequent decline in progesterone concentration.

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.

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