The incidence of luteal activity, as determined by peripheral plasma progesterone concentration, before the onset of the breeding season in the Rasa Aragonesa breed of sheep

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.

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

Canadian Journal of Animal Science ◽

10.4141/cjas72-076 ◽

1972 ◽

Vol 52 (4) ◽

pp. 645-658 ◽

Cited By ~ 54

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.

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

Journal of Endocrinology ◽

10.1677/joe.0.0520023 ◽

1972 ◽

Vol 52 (1) ◽

pp. 23-36 ◽

Cited By ~ 80

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.

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

Journal of Endocrinology ◽

10.1677/joe.0.0450449 ◽

1969 ◽

Vol 45 (3) ◽

pp. 449-457 ◽

Cited By ~ 114

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.

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Peripheral plasma progesterone and oestradiol concentrations associated with successful and unsuccessful recovery of uterine embryos in rhesus monkeys with and without intra-uterine devices

Journal of Endocrinology ◽

10.1677/joe.0.0960281 ◽

1983 ◽

Vol 96 (2) ◽

pp. 281-286

Author(s):

A. G. Wheeler ◽

P. R. Hurst ◽

P. Eckstein

Keyword(s):

Menstrual Cycle ◽

Success Rate ◽

Rhesus Monkeys ◽

Plasma Samples ◽

Progesterone Concentration ◽

Plasma Progesterone ◽

Uterine Lumen ◽

Peripheral Plasma ◽

Embryo Transport

Concentrations of progesterone and oestradiol were measured in peripheral plasma samples collected at the time when the uteri of rhesus monkeys with an intra-uterine device (IUD) and those without an IUD were flushed in attempts to recover uterine embryos. The proportion of successful attempts in IUD-bearing monkeys was much lower than in the non-IUD-bearing animals. Steroid measurements indicated that this reduced success rate was not due to an effect of the IUD on the timing of ovulation within the menstrual cycle or to a steroid-mediated disturbance in the rate of embryo transport to the uterine lumen. Successful embryo recoveries were associated with a higher progesterone concentration, suggesting that one reason for failure was that the attempt had been made too close to ovulation. There was no evidence of any asymmetry between the left or right ovaries in their ovulatory or steroidogenic activity.

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The use of Cloprostenol and prostaglandin F2alpha to induce luteolysis in reindeer calves (Rangifer tarandus)

Rangifer ◽

10.7557/2.11.1.968 ◽

1991 ◽

Vol 11 (2) ◽

pp. 13 ◽

Cited By ~ 4

Author(s):

Erik Ropstad ◽

Dag Lenvik

Keyword(s):

Breeding Season ◽

Rangifer Tarandus ◽

Prostaglandin F2alpha ◽

Progesterone Concentration ◽

Plasma Progesterone ◽

Blood Samples ◽

Treatment Groups ◽

Significant Fall

A total of 126 reindeer of about 7 months of age, were isolated from a flock at the end of the breeding season. The animals were treated either with 12.5 mg prostaglandin F2alpha (n = 41) or 0.25 mg cloprostenol (n = 50). Thirty-five animals were left untreated. Blood samples were collected before treatment and 2 Vi days later and the plasma progesterone concentrations were determined. A significant fall in progesterone concentration was seen in both treatment groups. A large proportion of animals responded to treatment with cloprostenol than with prostaglandin F2alpha. It was concluded that prostaglandins can be used to induce luteolysis in reindeer.

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Selected Factors that Affect the Measurement of Plasma Progesterone Concentrations in Pregnant Ewes

Australian Journal of Biological Sciences ◽

10.1071/bi9740659 ◽

1974 ◽

Vol 27 (6) ◽

pp. 659 ◽

Cited By ~ 3

Author(s):

AR Gleeson ◽

GD Thorburn

Keyword(s):

Protein Binding ◽

Diurnal Variation ◽

Significant Positive Correlation ◽

Plasma Samples ◽

Elevated Plasma ◽

Progesterone Concentration ◽

Plasma Progesterone ◽

Blood Samples ◽

Peripheral Plasma ◽

Competitive Protein Binding

A competitive protein-binding technique was used to measure progesterone concentrations in the peripheral plasma of pregnant ewes. Neither haemolysis of blood nor thawing of plasma samples affected plasma progesterone concentration. Blood samples should be chilled immediately upon collection but subsequent to centrifugation immediate chilling of the plasma samples is not critical. No consistent diurnal variation in progesterone concentrations was evident but there was large apparently random day-to-day variation in progesterone concentrations for any ewe. Although a significant positive correlation was found between endogenous progesterone and corticosteroid concentrations, the present study failed to correlate experimentally elevated plasma corticosteroid concentrations with progesterone concentrations. Progesterone concentrations varied greatly between ewes at the same stage of pregnancy.

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PERIPHERAL PLASMA PROGESTERONE CONCENTRATION DURING PERIPARTURIENT PERIOD IN BLACK BENGAL GOATS

Biology of Reproduction ◽

10.1093/biolreprod/77.s1.173c ◽

2007 ◽

Vol 77 (Suppl_1) ◽

pp. 173-173 ◽

Cited By ~ 1

Author(s):

S Mondal ◽

M C Pathak ◽

D N Singh ◽

V P Varshney

Keyword(s):

Progesterone Concentration ◽

Plasma Progesterone ◽

Peripheral Plasma ◽

Periparturient Period

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CIRCADIAN VARIATIONS IN PLASMA PROGESTERONE IN THE LUTEAL PHASE OF THE MENSTRUAL CYCLE AND DURING PREGNANCY

Acta Endocrinologica ◽

10.1530/acta.0.0690731 ◽

1972 ◽

Vol 69 (4) ◽

pp. 731-738 ◽

Cited By ~ 18

Author(s):

B. Runnebaum ◽

W. Rieben ◽

A.-M. Bierwirth-v. Münstermann ◽

J. Zander

Keyword(s):

Liquid Chromatography ◽

Menstrual Cycle ◽

Luteal Phase ◽

Circadian Variation ◽

Significant Rise ◽

Gas Liquid Chromatography ◽

Progesterone Concentration ◽

Circadian Variations ◽

Plasma Progesterone ◽

Peripheral Plasma

ABSTRACT Serial plasma progesterone determinations were performed by gas-liquid chromatography in healthy women during 24 hour periods during the luteal phase of the cycle and during pregnancy. In 10 women during the hyperthermic phase of the cycle and in 14 women during early pregnancy (week 8–18) no significant circadian variation in the peripheral plasma progesterone concentration was observed. During later pregnancy (week 20–41) in 15 women, a statistically significant rise in the plasma progesterone concentration, usually from 8.00 a.m. until between 4.00 and 8.00 p. m. followed by a decrease after 8.00 p. m. until between 4.00 and 8.00 a. m., was demonstrated. The data indicate a diurnal change in the peripheral plasma progesterone level during the last trimester of pregnancy.

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