Role of plasma progesterone concentration in early pregnancy of the ewe

1981 ◽  
Vol 21 (113) ◽  
pp. 562 ◽  
Author(s):  
FD Brien ◽  
IA Cumming ◽  
IJ Clarke ◽  
CS Cocks

Eighty-eight maiden and 125 mature Merino ewes were grazed on green irrigated pasture or given dry hay on a fallow area with or without a lupin grain supplement just before and during mating. Progesterone concentrations in peripheral plasma were measured at 12 d after coitus. Progesterone concentration was lower (2.27 vs 2.87 ng/ml, P < 0.001 ) when lupins were fed, and maiden ewes had higher progesterone concentrations than mature ewes (2.75 vs 2.36 ng/ml, P < 0.05). Pregnant ewes had higher progesterone concentrations than non-pregnant ewes (2.77 vs 2.36 ng/ml, P < 0.05), and ewes with two ovulations had higher progesterone concentrations than ewes with a single ovulation (3.13 vs 2.08 ng/ml, P < 0.001). There was an interaction between pasture type and lupin supplement, with lupins depressing progesterone level more on green irrigated pasture (lupins 2.11 ng/ml, no lupins 3.00 ng/ml, P < 0.05) than on dry pasture (lupins 2.45 ng/ml, no lupins 2.74 ng/ml, P < 0.05). The results confirm that a high plane of nutrition at mating lowers progesterone levels in plasma and suggest that this may be a factor in the increase in embryo deaths when ewes are fed lupin grain supplements.

1972 ◽  
Vol 52 (4) ◽  
pp. 645-658 ◽  
Author(s):  
H. A. ROBERTSON

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.


1969 ◽  
Vol 45 (3) ◽  
pp. 449-457 ◽  
Author(s):  
J. M. BASSETT ◽  
TANA J. OXBORROW ◽  
I. D. SMITH ◽  
G. D. THORBURN

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.


1972 ◽  
Vol 69 (4) ◽  
pp. 739-746 ◽  
Author(s):  
B. Runnebaum ◽  
K. Holzmann ◽  
A.-M. Bierwirth-v. Münstermann ◽  
J. Zander

ABSTRACT The influence of intravenous HCG infusions lasting for 2 hours on the peripheral plasma progesterone concentrations was investigated in healthy women on day 5 during the hyperthermic phase of the menstrual cycle and during week 6–19 and 31–39 of pregnancy. During the luteal phase the peripheral plasma progesterone level can be increased, on an average, up to 70 % with 5000 IU and up to 250 % with 20 000 IU. The highest plasma progesterone concentrations were reached about 8 hours after the beginning of the HCG infusion. In some experiments significantly elevated progesterone concentrations were still observed 20 hours after starting the HCG infusion. The results of intravenous HCG stimulation experiments during early pregnancy (10 000–20 000 IU) and during late pregnancy (5000–20 000 IU) showed no marked changes in the peripheral plasma progesterone concentrations.


1999 ◽  
Vol 42 (2) ◽  
pp. 183-190
Author(s):  
F. Rehbock ◽  
F. Schneider ◽  
S. Zupp ◽  
S. Grumbach

Abstract. Title of the paper: Seasonal influences on blood plasma progesterone concentration in ewes of Black head Mutton sheep breed (short communication) In 71 Black head mutton sheeps on pasturing and housing were determined from the year 1995 to 1997 and there in the period from March to October the concentration of blood progesterone for determination of onset of estrus. The level of blood progesterone reported, on literature also, no cycle on this period. The investigation of 6 of this sheeps with ultrasonography had the result of ovarian activity with follicles from 2 mm to 7 mm in diameter, but no cycle was determined. The progesterone level of minimum and maximum on all years differed from March to beginning of September between 0,33 ng/ml and 2,15 ng/ml blood progesterone, after this to October between 0,82 ng/ml and 4,25 ng/ml blood progesterone. The pregnant sheeps detected blood progesterone concentrations from 5,50 ng/ml to 13,55 ng/ml blood progesterone (twins). The corpus luteum activity may be is prevalent on the blood progesterone level up 2 ng/ml and pregnancy up 5 ng/ml blood progesterone. The detectability of blood progesterone and supplemented ultrasonography of ovary possess the possibility recording of onset cycle activity and early pregnancy diagnosis.


1970 ◽  
Vol 65 (3_Suppl) ◽  
pp. S5-S32 ◽  
Author(s):  
K. Loewit

ABSTRACT The role of luteinizing hormone (LH) for the maintenance of pregnancy, parturition and lactation was investigated by immunological and histochemical methods in the rat. Neutralisation of endogenous rat-LH with Rabbit-Anti-Bovine-LH-Serum (selective hypophysectomy) from days 7-12 of pregnancy resulted in reabsorption of the foetuses and the reappearance of strong 20α-hydroxysteroid-dehydrogenase (20α-OHSD) activity in the corpora lutea (CL) of pregnancy, which normally show no such activity at that time. This effect could be prevented in part by concurrent pregnenolone administration and fully by progesterone, but was not influenced by oestrogen or prolactin. It is concluded that in early pregnancy LH is the main luteotrophic hormone in the rat even though prolactin might act synergistically with it. Antiserum treatment after the 12th day of gestation had no influence on the state or duration of pregnancy or on parturition. LH-injections during the first half of pregnancy had no luteolytic effects i. e. they did not activate 20α-OHSD activity. After day 16 they advanced the reappearance of the enzyme, but delayed parturition or resulted in stillbirths. Neither LH nor antiserum seemed to alter lactation. Since progesterone prevented both the termination of pregnancy and the recurrence of 20α-OHSD activity, it should have some regulatory properties on the enzyme. It is discussed whether the gonadotrophin-dependent progesterone level could regulate the 20α-OHSD activity rather than result from it.


2009 ◽  
Vol 21 (1) ◽  
pp. 254
Author(s):  
A. Gaja ◽  
C. Kubota ◽  
T. Kojima

The present study aims to establish a novel practical protocol for early pregnancy diagnosis in cows by using transrectal ultrasonography. The protocol is based on measurements of corpus luteum (CL) cross-sectional area (CL c-s area) change performed at 2 separate days before the coming estrus after AI. Fourteen cows were inseminated artificially, and transrectal ultrasonographical observation of the ovaries and blood collection for measurement of peripheral plasma progesterone (P4) concentration were carried out daily from Days 12 to 23 (Day 0 = the day of onset of estrus). Thereafter, cows were routinely diagnosed for pregnancy at Day 30 by transrectal ultrasonography. The largest CL c-s area was obtained at Day 14 in both pregnant and non-pregnant cows. Seven out of 8 non-pregnant cows showed significant CL c-s area regression between Days 14 and 20 (422 ± 112 v. 249 ± 63 mm2), whereas no regression was observed between Days 14 and 20 in pregnant cows (416 ± 65 v. 402 ± 78 mm2). The regression in the CL c-s area between pregnant and non-pregnant cows was significantly different during Day 18 (424 ± 65 v. 288 ± 88 mm2) to Day 23 (402 ± 71 v. 139 ± 64 mm2). P4 concentration was significantly low (less than 1 ng mL–1) at Day 20 in 3 out of 8 non-pregnant cows, whereas the pregnant cows showed significant increase of P4 between Days 14 and 20 (2.6 ± 0.2 v. 3.4 ± 0.5 ng mL–1). The pregnant cows showed significantly higher P4 concentration starting from Day 18 than non-pregnant cows. However, in non-pregnant cows, 4 cows returned to estrus on Day 20 or after, 3 cows showed no signs of estrus, and 1 cow came in estrus as early as Day 18 after AI. In conclusion, the results of the present study suggest that measuring the change in the CL c-s area at Days 14 and 20 makes it possible to detect the non-pregnant cows at Day 20 after AI. However, it was also indicated that measuring the change of P4 concentrations on the same days did not always successfully detect non-pregnant cows. The new protocol based on CL c-s area regression rate can detect almost certainly non-pregnant cows at Day 20 after AI. It is suggested that this method is advantageous in research and industrial breeding.


2006 ◽  
Vol 54 (3) ◽  
pp. 211 ◽  
Author(s):  
Y. P. Cruz ◽  
H. Morton ◽  
A. C. Cavanagh ◽  
L. Selwood ◽  
S. D. Wilson ◽  
...  

Maternal recognition of pregnancy in marsupials occurs in more subtle ways than it does in eutherians. For instance, unlike in eutherians, the plasma progesterone profiles of pregnant and non-pregnant animals are similar during the luteal phase. It is typically during the brief luteal phase that both gestation and parturition occur in marsupials. Yet histological and physiological changes have been documented between gravid and non-gravid uteri in certain monovular marsupials and between pregnant and non-pregnant animals in polyovular marsupials. Early pregnancy factor (EPF), a 10.8-kDa serum protein known to be homologous to chaperonin 10, is associated with maternal immunosuppression, embryonic development and pregnancy in eutherian mammals. It has been reported in two Australian marsupials: the dasyurid Sminthopsis macroura and the phalangerid Trichosurus vulpecula. This paper documents its occurrence in the New World didelphid Monodelphis domestica. EPF is detectable by rosette inhibition assay in the peripheral circulation of pregnant but not of non-pregnant or pseudopregnant animals. Our work focuses on the embryo–maternal signalling role of EPF during pregnancy. Because progesterone-driven changes are similar in pregnant and non-pregnant marsupials, these animals are an excellent laboratory model in which to investigate the role of EPF in orchestrating the physiological changes necessary to sustain pregnancy.


1970 ◽  
Vol 48 (4) ◽  
pp. 599-614 ◽  
Author(s):  
L. E. DONALDSON ◽  
J. M. BASSETT ◽  
G. D. THORBURN

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.


1972 ◽  
Vol 52 (1) ◽  
pp. 23-36 ◽  
Author(s):  
G. D. THORBURN ◽  
W. SCHNEIDER

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.


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