SEQUENTIAL CHANGES IN PLASMA PROGESTERONE LEVELS IN THE EWE DURING THE ESTROUS CYCLE, AND DURING PREGNANCY IN INTACT AND OVARIECTOMIZED SHEEP

1973 ◽  
Vol 53 (1) ◽  
pp. 25-34 ◽  
Author(s):  
I. R. SARDA ◽  
H. A. ROBERTSON ◽  
T. C. SMEATON
Keyword(s):  
Estrous Cycle ◽  
Population Sample ◽  
Maximum Level ◽  
Individual Variability ◽  
Progesterone Concentration ◽  
Sharp Rise ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
The Individual ◽  
Second Peak

The progesterone concentration in the peripheral plasma was measured sequentially in individual ewes during the estrous cycle, and during gestation and parturition in intact and in ovariectomized ewes. Progesterone levels during anestrum and in ovariectomized ewes have been measured. During the estrous cycle the concentration was lowest (0.1–0.2 ng/ml) from 36 h before to 48 h after, the onset of estrus. A similar concentration was found during anestrum and in ovariectomized ewes, suggesting that at estrus the progesterone comes from nonovarian tissue, probably the adrenal gland. On the 4th day of the cycle (day of estrus = 1st day) the progesterone level began to rise reaching a peak of 1.9–4.0 ng/ml on the 10th day. After a decline, the level rose to a second peak on the 14th or 15th day. Three to 4 days before the next onset of estrus the concentration dropped sharply over a period of 48 h to a low basal level (0.1–0.2 ng/ml). During early pregnancy the plasma progesterone concentration remained fairly constant at a level similar to the maximum level found during the cycle. A sharp rise started around the 80th day, reaching 15–20 ng/ml around the 110th day. This was followed by a second peak, then a decline in the plasma progesterone concentration before parturition, but the time at which this began was variable (1–11 days) and even on the day of parturition the level was generally > 3 ng/ml. A basal level of < 0.5 ng/ml was reached within 24 h after parturition. Pregnancy in ewes ovariectomized soon after conceiving was maintained with implants of progesterone. When these implants were removed around the 90th day of pregnancy the plasma progesterone concentration showed a similar rise to that which occurred in intact pregnant ewes at this time. Parturition occurred normally in these ewes. Within the limited population sample, any relation between the plasma progesterone and the number, sex, or weight of the fetus (es) was masked by the individual variability in the concentration of progesterone.

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.

Progesterone levels in peripheral plasma of Rocky Mountain bighorn ewes (Ovis canadensis) during the estrous cycle and pregnancy

1980 ◽  
Vol 58 (6) ◽  
pp. 1105-1108
Author(s):  
P. E. Whitehead ◽  
E. H. McEwan
Keyword(s):  
Estrous Cycle ◽  
Rocky Mountain ◽  
Ovis Canadensis ◽  
Rapid Decline ◽  
Plasma Progesterone ◽  
Peripheral Plasma

Plasma progesterone levels of three Rocky Mountain bighorn ewes (Ovis canadensis) were determined during anestrus, estrus, and pregnancy. Eighteen-month-old ewes had "silent" heats with peak progesterone levels ranging from 1.0 to 2.2 ng/mL. At [Formula: see text] years of age, luteal activity preceded behavioural estrus and successful breeding. During the first 50 days of gestation, plasma progesterone levels increased to 8.5 ng/mL (8.0–9.2 ng/mL). From 50 to 80 days, progesterone levels decreased, followed by an increase to peak values of 13.3 to 23.2 ng/mL. A rapid decline in progesterone levels occurred about the time of parturition.

LUTEINIZING HORMONE (LH) AND PROGESTERONE IN PLASMA AND LH AND OESTROGENS IN URINE DURING 42 NORMAL MENSTRUAL CYCLES

1971 ◽  
Vol 68 (3) ◽  
pp. 502-512 ◽  
Author(s):  
Elof D. B. Johansson ◽  
Leif Wide ◽  
Carl Gemzell
Keyword(s):  
Luteinizing Hormone ◽  
Urinary Excretion ◽  
Plasma Levels ◽  
Luteal Phase ◽  
Maximum Level ◽  
Plasma Progesterone ◽  
Menstrual Cycles ◽  
Normal Menstrual Cycle ◽  
The Mean ◽  
Second Peak

ABSTRACT The plasma levels of luteinizing hormone (LH) and progesterone and the urinary excretion of LH and oestrogens were measured during the normal menstrual cycle of 22 young and healthy women. A total of 42 cycles were investigated. The urinary excretion of total oestrogens increased during several days before the rise of LH in the urine. The day of maximum excretion of LH and total oestrogens coincided during the midcycle period. The mid-cyclic rise in LH was found to occur on the same day in the plasma and urine and the days of maximum values coincided in 11 out of 16 cycles. In 5 cycles the maximum level was reached one day later in the urine. The plasma levels of progesterone started to increase during the LH and oestrogen peaks. The days for maximum levels of progesterone coincided with the second peak of urinary oestrogens. The levels of progesterone in the plasma reached values above 10 ng per ml in all normal cycles. The plasma levels of progesterone were below 1 ng per ml plasma when menstrual bleeding started. The length of the luteal phase was 14.4 ± 1.1 (s) days. The sum of daily urinary excretion of total oestrogens and the sum of the daily plasma progesterone levels varied within 15 per cent of the mean in five out of six women studied during more than two cycles. The variation in values for the sums of daily oestrogen excretion and plasma progesterone levels was considerably larger between menstrual cycles of different women than between menstrual cycles of the same woman.

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.

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.

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.

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

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.

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

1974 ◽  
Vol 27 (6) ◽  
pp. 659 ◽  
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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