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.

OESTROGEN, PROGESTERONE AND CORTICOSTEROID CONCENTRATIONS IN PERIPHERAL PLASMA OF SOWS DURING PREGNANCY, PARTURITION, LACTATION AND AFTER WEANING

1975 ◽  
Vol 64 (1) ◽  
pp. 141-154 ◽  
Author(s):  
R. W. ASH ◽  
R. B. HEAP
Keyword(s):  
Steroid Hormone ◽  
Late Pregnancy ◽  
Cortisol Concentration ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
The Third ◽  
Peripheral Plasma ◽  
Consistent Change ◽  
Foetal Blood ◽  
Venous Plasma

SUMMARY Steroid hormone concentrations in plasma have been measured in blood samples taken from conscious sows with ear vein catheters. In late pregnancy, the plasma progesterone concentration ranged from 6 to 12 ng/ml and it decreased in all animals before the onset of parturition. Total unconjugated oestrogens increased to high values of up to about 3 ng/ml in late pregnancy and then declined after the onset of parturition. Oestrone was the predominant unconjugated oestrogen measured. Plasma corticosteroid (mainly cortisol) concentration was about 33 ng/ml and showed no consistent change at the time of parturition. During lactational anoestrum the plasma concentration of progesterone and total unconjugated oestrogens was very low, while that of corticosteroids was 21 ng/ml. When the piglets were weaned at 26–31 days, sows came into oestrus 4–12 days later, and this was preceded, or accompanied by, an increase in plasma oestrogens. In the luteal phase, plasma progesterone concentrations rose to 20–35 ng/ml. A sow whose piglets were removed at birth, showed signs of oestrus (vulval enlargement and a lordosis response), but a lack of receptivity to the boar associated with no detectable changes in the plasma oestrogen concentration; however, ovulation probably occurred since plasma progesterone values increased in a manner comparable to that found after the formation of normal corpora lutea in other sows. After a second non-receptive cycle, the sow was mated and became pregnant at the third post-weaning oestrus. At parturition the concentration of progesterone and total unconjugated oestrogens was greater in placental venous plasma than in maternal jugular plasma, which indicates placental synthesis of these hormones. A greater concentration of plasma corticosteroids in foetal blood than in placental venous or maternal jugular plasma suggests foetal synthesis in late pregnancy.

A note on attainment of puberty of september-born early-maturing ewe lambs in relation to level of nutrition

1991 ◽  
Vol 53 (3) ◽  
pp. 407-409 ◽  
Author(s):  
F. Forcada ◽  
J. A. Abecia ◽  
L. Zarazaga
Keyword(s):  
Sexual Activity ◽  
Breeding Season ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Plasma Progesterone ◽  
Ewe Lambs ◽  
Early Maturing ◽  
Age At Puberty

The attainment of puberty in September-born early-maturing ewe lambs was studied at Zaragoza (latitude 41° 40' N). Thirty twin Salz females were allocated to two groups receiving two nutrition levels after 3 months of age: high (500 g/day lucerne hay and 500 g/day concentrate) (H) and low (500 g/ day lucerne hay) (L). Oestrus was detected daily by aproned rams. Corpora lutea were counted after oestrus and plasma progesterone levels monitored each week.In the first breeding season (January to February) the percentage of females showing sexual activity (silent emulation or oestrus and ovulation) was higher in the H compared with the L group (67 and 20%; P < 0/05). Nonpubertal oestrus before the main breeding season was detected in 67% of animals. In the main breeding season and for H and L groups respectively, percentage of females showing silent ovulation before puberty was 67 and 33% and mean age at puberty extended to 319 (s.e. 4-8) and 314 (s.e. 3·7) days. Ovulation rate at puberty was 1·73 (s.e. 0·13) and 1·33 (s.e. 0·15) respectively (P < 0·05).

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

Effects of naloxone and electroacupuncture treatment on plasma concentrations of LH in sheep

1984 ◽  
Vol 101 (1) ◽  
pp. 75-80 ◽  
Author(s):  
P. V. Malven ◽  
D. F. B. Bossut ◽  
M. A. Diekman
Keyword(s):  
Breeding Season ◽  
Luteal Phase ◽  
Plasma Concentrations ◽  
Opioid Antagonist ◽  
Similar Treatment ◽  
Plasma Progesterone ◽  
Electroacupuncture Treatment

ABSTRACT Mature ewes were injected intravenously with the opioid antagonist naloxone (1·1 mg/kg) during the breeding season. Ewes with luteal phase concentrations of plasma progesterone responded with a significant (P <0·05) increase in plasma LH 14–23 min after naloxone injection. In contrast, non-luteal ewes with low plasma progesterone did not respond to injection of naloxone with an LH increase. Similar treatment of castrated males (wethers) with this dosage of naloxone failed to increase plasma LH. Electroacupuncture (EA) treatment of luteal phase ewes prevented the ability of exogenous naloxone to increase plasma LH. Treatment of wethers by EA decreased significantly (P <0·01) their high basal concentrations of plasma LH, but similar EA treatment of intact ewes did not change their low basal concentrations of LH. J. Endocr. (1984) 101, 75–80

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.

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.

Progesterone and oestrogen receptors in the female genital tract throughout pregnancy in tammar wallabies

Reproduction ◽  
2000 ◽  
pp. 121-128 ◽  
Author(s):  
MB Renfree ◽  
DR Blanden
Keyword(s):  
Reproductive Tract ◽  
Limit Of Detection ◽  
Post Partum ◽  
Single Point ◽  
Female Genital Tract ◽  
Late Pregnancy ◽  
Gravid Uterus ◽  
Plasma Progesterone ◽  
Peripheral Plasma ◽  
Point Analysis

The tammar, Macropus eugenii, is a monovular macropodid marsupial which has a post-partum oestrus and an 11 month embryonic diapause. Progesterone and oestradiol cytosol receptors were measured by Scatchard analyses and single point analysis in the lateral vagina, endometrium and myometrium of the gravid and contralateral non-gravid uterus throughout pregnancy, immediately after parturition and during seasonal reproductive quiescence. In endometrial tissues, both progesterone and oestradiol receptors doubled in concentration in both gravid and non-gravid uteri between day 0 and day 5 of pregnancy, coinciding with previously described peak values in peripheral plasma progesterone and oestrogen. Receptor concentrations in endometrial tissue during seasonal quiescence were not significantly different from those immediately after reactivation. After day 12 of pregnancy, downregulation of both progesterone and oestradiol cytosolic receptors occurred concomitant with the increase in progesterone in the peripheral plasma. However, there was a unilateral increase in oestradiol receptor concentrations in endometrium obtained from the non-gravid uterus between day 25 of the 26.5 day gestation and immediately after parturition. Myometrial receptor concentrations mirrored those of the endometrium but were lower. Concentrations of progesterone receptor in the lateral vaginae were at the lower limit of detection, while the oestradiol cytosol receptor concentrations were even lower in this tissue. Thus, the steroid receptor concentrations provide another example of local unilateral endocrine responses in the reproductive tract of the tammar. These results also indicate that the downregulation of progesterone and oestradiol receptors that occurs in both uteri in mid- and late-pregnancy is selectively and locally reversed before parturition in the non-gravid endometrium in response to the local effects of follicular oestradiol from the ipsilateral ovary.

Effect of ovariectomy on the course of gestation in the grey squirrel (Sciurus carolinensis)

1982 ◽  
Vol 93 (3) ◽  
pp. 423-426 ◽  
Author(s):  
G. E. Webley ◽  
Elizabeth Johnson
Keyword(s):  
Early Pregnancy ◽  
Sciurus Carolinensis ◽  
Corpora Lutea ◽  
Grey Squirrel ◽  
Plasma Progesterone ◽  
In The Wild

In the grey squirrel pregnancy continues in the absence of the ovaries from day 16 of gestation. Since the investigation was performed on squirrels caught in the wild the stage of gestation was estimated from plasma progesterone levels, volume of corpora lutea at ovariectomy and date of parturition for those squirrels which did give birth. Three squirrels ovariectomized in early pregnancy did not give birth. Plasma progesterone levels after ovariectomy were lower than those found in normal pregnant squirrels suggesting that the corpora lutea are a continuing source of progesterone even at a time when pregnancy can continue in their absence.

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