Studies on Marsupial Reproduction. 2. The oestrous cycle of Setonix Brachyurus.

1955 ◽  
Vol 3 (1) ◽  
pp. 44 ◽  
Author(s):  
GB Sharman
Keyword(s):  
Corpus Luteum ◽  
Blood Vessels ◽  
Mitotic Activity ◽  
Rapid Growth ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Degenerative Changes ◽  
Vaginal Smear ◽  
In The Wild ◽  
Uterine Glands

Setonix brachyurus Quoy and Gaimard is polyoestrous, the length of the cycle being about 28 days. In the wild and in the newly domesticated female, oestrous cycles are resumed in late January after an anoestrous period of 3-5 months. During this period oestrus does not occur and ovary and uterus are shrunken and quiescent. Domestication for periods exceeding 1 yr results in a greatly shortened anoestrous period, culminating in a condition in which oestrus is repeated at regular monthly intervals throughout the year. Pro-oestrus is accompanied by rapid growth of one Graafian follicle, mitotic activity in the uterus, and usually by the onset of cornification in the vaginae and appearance of partly cornified cells in the smear. At oestrus the largest follicle reaches a diameter of almost 3.0 mm. Behavioural oestrus lasts about 12 hr. Ovulation follows 12-24 hr after oestrus and is independent of the act of copulation. Invasion of the collapsed follicle by blood vessels and the growth of a corpus luteum takes place after ovulation. Under the influence of the corpus luteum a luteal phase occurs in the uterus and lasts until about 18 days after oestrus. During the period of activity of the corpus luteum the vaginal smear is almost entirely composed of non-cornified cells and leucocytes. Following the cessation of the luteal phase degenerative changes occur in the uterus and the uterine glands are invaded by leucocytes. The changes during the oestrous cycle in Setonix are compared with those occurring in Didelphis and in other marsupials.

A comparative study of the corpus luteum

1995 ◽  
Vol 7 (3) ◽  
pp. 303 ◽  
Author(s):  
RT Gemmell
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Hormonal Control ◽  
Egg Laying ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Embryonic Diapause ◽  
Alternative Reproductive Strategy ◽  
Uterine Development

The corpus luteum (CL) is a transitory organ which has a regulatory role in reproduction. Sharks, amphibians and reptiles have corpora lutea that produce progesterone which influences the rate of embryonic development. The egg-laying monotremes and the two major mammalian groups, eutherian and marsupial, have a CL that secretes progesterone. Most eutherians have allowed for the uterine development of their young by extending the length of the oestrous cycle and the CL or placenta actively secretes progesterone until birth. Gestation in the marsupial does not extend beyond the length of an oestrous cycle and the major part of fetal development takes place in the pouch. Where the extension of the post-luteal phase in the eutherian has allowed for the uterine development of young, the marsupial has extended the pre-luteal phase of the oestrous cycle and has evolved an alternative reproductive strategy, embryonic diapause. The mechanism for the secretion of hormones from the CL has been controversial for many years. Densely-staining secretory granules have been observed in the CL of sharks, marsupials and eutherians. These granules have been reported to contain relaxin, oxytocin or mesotocin, and progesterone. A hypothesis to suit all available data is that all hormones secreted by the CL are transported within such granules. In conclusion, although there are obvious differences in the mode of reproduction in the two main mammalian groups, it is apparent that there is a great deal of similarity in the hormonal control of regression of the CL and parturition.

scholarly journals Delayed effect of low progesterone concentrations on bovine uterine PGF(2alpha) secretion in the subsequent oestrous cycle

Reproduction ◽  
2001 ◽  
pp. 643-648 ◽  
Author(s):  
A Shaham-Albalancy ◽  
Y Folman ◽  
M Kaim ◽  
M Rosenberg ◽  
D Wolfenson
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Delayed Effect ◽  
Plasma Progesterone ◽  
Progesterone Secretion ◽  
Progesterone Treatment ◽  
Late Luteal Phase ◽  
Subsequent Cycle ◽  
Concentration Curves

Low progesterone concentrations during the bovine oestrous cycle induce enhanced responsiveness to oxytocin challenge late in the luteal phase of the same cycle. The delayed effect of low progesterone concentrations during one oestrous cycle on uterine PGF(2alpha) secretion after oxytocin challenge on day 15 or 16 of the subsequent cycle was studied by measuring the concentrations of the major PGF(2alpha) metabolite (13,14-dihydro-15-keto PGF(2alpha); PGFM) in plasma. Two experiments were conducted, differing in the type of progesterone treatment and in the shape of the low progesterone concentration curves. In Expt 1, progesterone supplementation with intravaginal progesterone inserts, with or without an active corpus luteum, was used to obtain high, or low and constant plasma progesterone concentrations, respectively. In Expt 2, untreated cows, representing high progesterone treatment, were compared with cows that had low but increasing plasma progesterone concentrations that were achieved by manipulating endogenous progesterone secretion of the corpus luteum. Neither experiment revealed any differences in plasma progesterone concentrations between the high and low progesterone groups in the subsequent oestrous cycle. In both experiments, both groups had similar basal concentrations of PGFM on day 15 (Expt 1) or 16 (Expt 2) of the subsequent oestrous cycle, 18 days after progesterone treatments had ended. In both experiments, the increases in PGFM concentrations in the low progesterone groups after an oxytocin challenge were markedly higher than in the high progesterone groups. These results indicate that low progesterone concentrations during an oestrous cycle have a delayed stimulatory effect on uterine responsiveness to oxytocin during the late luteal phase of the subsequent cycle. This resulting increase in PGF(2alpha) secretion may interfere with luteal maintenance during the early stages of pregnancy.

Source of ovarian inhibin secretion during the oestrous cycle of the sheep

1989 ◽  
Vol 123 (2) ◽  
pp. 181-188 ◽  
Author(s):  
G. E. Mann ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Venous Blood ◽  
Contralateral Side ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Secretion Rate ◽  
Antral Follicles ◽  
Luteal Tissue

ABSTRACT The source of inhibin secretion by the ovary in the sheep at different stages of the oestrous cycle was investigated by in-vivo cannulation of the ovarian veins. Twenty-four Scottish Blackface ewes were allocated to four groups of six ewes, i.e. those operated on during the luteal phase (day 10), and those operated on during the follicular phase 24–30, 36 and 60 h following an injection of 125 μg cloprostenol on day 10 of the luteal phase. Samples of jugular and timed ovarian venous blood were collected under anaesthesia before and after enucleation of the corpus luteum. Ovaries were then removed and follicles dissected out. Following injection of cloprostenol, luteal regression occurred as indicated by a fall in the secretion of progesterone. The concentration of inhibin in jugular venous plasma and its ovarian secretion rate were similar at all stages of the follicular phase and during the luteal phase. In contrast, the secretion rate of oestradiol rose from 2·68 ±0·73 pmol/min during the luteal phase to 8·70± 2·24 pmol/min 24 h after injection of cloprostenol (P<0·05). Following enucleation of the corpus luteum the secretion rate of progesterone fell from 809 ± 270 pmol/min to 86 ± 30 pmol/min (P<0·001). There was also a smaller, artifactual fall in the secretion rate of oestradiol following enucleation of the corpus luteum, which was of similar size to a fall seen in the secretion rate of inhibin. This resulted in a significant (P<0·001) fall in the ratio of progesterone to inhibin, while the oestradiol to inhibin ratio remained unchanged. The secretion rate of inhibin from ovaries containing luteal tissue was similar to that from the contralateral side without luteal tissue (1·41±0·30 compared with 1·32±0·30 ng/min), while ovaries with large antral follicles secreted significantly (P< 0·001) more inhibin than those with no follicles ≥3 mm (2·28 ± 0·36 compared with 0·25 ±0·06 ng/min). From these results we conclude that, in the sheep, large antral follicles are responsible for most, if not all, the secretion of inhibin by the ovary at all stages of the oestrous cycle, and that the corpus luteum secretes little or no immunoactive or bioactive inhibin. Due to the fact that, unlike inhibin, the secretion rate of oestradiol rises during the follicular phase of the cycle, when the concentration of FSH is suppressed, it seems likely that oestradiol rather than inhibin is the major ovarian factor modulating the change in FSH secretion seen at this stage of the oestrous cycle. Journal of Endocrinology (1989) 123, 181–188

scholarly journals Luteal ANGPT-TIE system during selected stages of pregnancy, and normal and antigestagen-induced luteolysis in the dog.

Reproduction ◽  
2018 ◽  
Author(s):  
Aykut Gram ◽  
Miguel Tavares Pereira ◽  
Alois Boos ◽  
Anna T Grazul-Bilska ◽  
Mariusz P. Kowalewski
Keyword(s):  
Corpus Luteum ◽  
Blood Vessels ◽  
Luteal Phase ◽  
Vascular Network ◽  
Network Development ◽  
Luteal Cells ◽  
Time Points ◽  
Tunica Media ◽  
Post Implantation ◽  
Tunica Intima

Rapid establishment of a vascular network is essential for normal functionality of the corpus luteum (CL). The early luteal phase is associated with increased expression of the VEGF-system in canine CL. Acting in synchrony with angiopoietins (ANGPTs), VEGF-system plays major roles in stabilization of blood vessels. However, the expression of the ANPGT-system has not yet been investigated in the dog. Therefore, here, we investigated the luteal expression of ANGPT1, -2, and of their receptors TIE1 and -2, in pregnant dogs at selected time points during pregnancy and at normal and antigestagen-induced luteolysis. Additionally, luteal cells from early CL were incubated with PGE2 and its effects on the ANGPT-system were assessed. Whereas the luteal ANGPT1 was stable until mid-gestation, TIE1 was elevated post-implantation, their expression decreased towards prepartum luteolysis. The ANGPT2- and TIE2-mRNA did not vary during pregnancy. The ANGPT2/ANGPT1 ratio was elevated during prepartum luteolysis. PGE2 increased ANGPT2, but suppressed ANGPT1 levels. None of the ANGPT-system members was affected by antigestagen treatment in mid-pregnancy. Localization of ANGPT1 was predominantly found in the tunica intima and media of vessels and ANGPT2 stained strongly in luteal cells. Both ANGPTs were localized in macrophages. TIE1 stained in the vascular tunica media, in luteal cells and macrophages, whereas TIE2 was colocalized with ANGPT1 in vascular components. In conclusion, high expression of ANGPT1 during the increased presence of VEGFA in early canine CL implies its contribution to vascular network development. The upregulation of the ANGPT2/ANGPT1 ratio during prepartum luteolysis indicates involvement of the ANGPT-system in PGF2a-mediated vascular destabilization.

STUDIES ON THE BIOLOGY OF THE MUSKRAT IN MANITOBA: PART I. OESTROUS CYCLE AND BREEDING SEASON

1952 ◽  
Vol 30 (4) ◽  
pp. 243-253
Author(s):  
J. A. McLeod ◽  
G. F. Bondar
Keyword(s):  
Breeding Season ◽  
Cycle Length ◽  
Oestrous Cycle ◽  
Minimum Time ◽  
Vaginal Smear ◽  
In Captivity ◽  
In The Wild ◽  
The Mean ◽  
Time Required ◽  
Mean Time

A study of oestrus in female muskrats was conducted during the summers of 1950 and 1951 as part of a five year investigation of the biology of the muskrat in Manitoba. Two captive females examined daily by the vaginal smear method from June 30 to Aug. 10, 1950, inconclusively indicated an oestrous cycle length of about 30 days which agreed with the findings of Beer on Wisconsin muskrats. In 9151 10 female muskrats of various ages and of different lengths of time in captivity were examined daily beginning on March 13 and continuing until August 15. The data obtained at this time showed a considerable variation in the lengths of the oestrous cycles in different females or, even, in the same individual from time to time. The minimum time required for the completion of an oestrous cycle was found to be two days while the maximum time observed was 22 days. On the basis of 136 complete oestrous cycles studied, the modal time was found to be approximately four days and the mean time 6.1 days. The longer cycles found by ourselves in 1950 and by Beer are interpreted as representing pseudopregnancies and not oestrous cycles. Failure of muskrats to mate in captivity or in the wild during the latter part of the summer is attributed to sexual inactivity of the males and not the females.

Effects of local growth factors on the secretory function of bovine corpus luteum during the oestrous cycle and pregnancy in vitro

1996 ◽  
Vol 8 (6) ◽  
pp. 1003 ◽  
Author(s):  
J Liebermann ◽  
D Schams ◽  
A Miyamoto
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Corpus Luteum ◽  
Luteal Phase ◽  
Late Pregnancy ◽  
Oestrous Cycle ◽  
Tnf Alpha ◽  
Igf I ◽  
Factor Alpha

The impact of insulin-like growth factor-I (IGF-I) basic fibroblast growth factor (bFGF), endothelin-1 (ET-1), tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-alpha (TGF-alpha) and platelet-derived growth factor (PDGF) on the release of progesterone (P4) and oxytocin (OT) from individual bovine corpora lutea at different stages of the oestrous cycle and pregnancy was evaluated with a microdialysis system (MDS) in vitro. IGF-I (1 microgram mL-1) induced significantly the acute effects on P4 release at the late luteal stage (Days 15-18) and early pregnancy (Days 60-120), whereas bFGF (100 ng mL-1) was extremely effective in stimulating P4 release particularly during the mid-luteal stage (Days 8-12). Both peptides stimulated (P < 0.05) the release of OT throughout the three luteal stages and during early and late pregnancy (Days 30-60 and Days 150-210). ET-1 (100 ng mL-1) clearly inhibited P4 release during the early (Days 5-7) and mid-luteal phase and stimulated OT release only during the mid-luteal stage (P < 0.001). TNF-alpha (100 ng mL-1) stimulated the release of P4 exclusively at the early luteal phase (P < 0.05), whereas OT secretion was increased by TNF-alpha during all stages of the oestrous cycle (P < 0.001). TGF-alpha and PDGF (100 ng mL-1) were effective in stimulating P4 release particularly during late pregnancy (P < 0.05). In contrast, stimulation of OT secretion by TGF-alpha was maximal during the late-luteal stage (P < 0.001), whereas PDGF significantly increased OT secretion during the oestrous cycle (except the early luteal stage) and pregnancy (P < 0.001). The data demonstrate distinct and stage-specific effects of growth factors on P4 and OT secretion in vitro. IGF-I, bFGF and TGF-alpha may play an important role in corpus luteum (CL) function during the oestrous cycle and pregnancy since they are locally expressed and synthesized, there are receptors for these growth factors, and they have been demonstrated to exert biological effects on the CL.

The reproductive system and embryonic diapause in the female kangaroo, Marcopodus giganteus

1967 ◽  
Vol 15 (3) ◽  
pp. 441 ◽  
Author(s):  
MJ Clark ◽  
WE Poole
Keyword(s):  
Corpus Luteum ◽  
Mitotic Activity ◽  
Reproductive System ◽  
Luteal Phase ◽  
Post Partum ◽  
Ovarian Follicle ◽  
Initial Period ◽  
Secretory Cells ◽  
Ovarian Activity ◽  
Embryonic Diapause

The reproductive system of the female grey kangaroo consists as in other marsupiais, of two ovaries, two uteri, two lateral vaginae, and a median vaginal canal. The changes which occur during the oestrous cycle or pregnancy can be divided into three phases: (1) a proliferative phase characterized by maturation and rupture of an ovarian follicle and its subsequent transformation into a new corpus luteum, and by cell division in the uteri; (2) a luteal phase, when the corpus luteum is fully formed and the luteal cells attain their maximum size, and the uterine gland cells are tall columnar, with basally situated nuclei; and (3) a post-luteal phase when the secretory cells of the corpus luteum and uteri degenerate. Repair begins in the uteri before the end of pregnancy and this is supplemented by post-partum mitotic activity, but post-partum oestrus does not occur. The uterine glands are small, and ovarian activity is inhibited during the initial period of lactation. A small proportion of females with pouch young over 100 days old return to oestrus and mate. Mitotic activity then ceases in the uteri, in the newly formed corpus luteum, and the blastocyst until the pouch young is lost or approaches the end of pouch life, when mitotic activity is resumed in the corpus luteum and blastocyst. The occurrence of embryonic diapause has been confirmed in both wild and captive animals.

The effect of active and passive immunization against oxytocin on ovarian cyclicity in ewes

1983 ◽  
Vol 103 (3) ◽  
pp. 337-344 ◽  
Author(s):  
D. Schams ◽  
S. Prokopp ◽  
D. Barth
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Passive Immunization ◽  
Threshold Concentration ◽  
High Variability ◽  
Oestrous Cycle ◽  
Ovarian Cyclicity

Abstract. Active and passive immunization of ewes against oxytocin prolonged the luteal phase of the oestrous cycle, as evaluated by oestrus behaviour and determination of progesterone. Between the animals there was a high variability in response. In general animals with prolonged cycles had lower concentrations of free oxytocin. But in some animals oxytocin antibodies had no effect on cyclicity. Therefore, an individual minimal threshold concentration for oxytocin was presumed. In control or treated animals circulating oxytocin concentrations increased parallel with progesterone concentrations but decreased earlier during the mid luteal phase of the cycle. A new increase in oxytocin concentrations was only observed if a new corpus luteum was formed.

Reproduction in Captive Female Brushtail Possums, Trichosurus-Vulpecula

1986 ◽  
Vol 34 (1) ◽  
pp. 47 ◽  
Author(s):  
JD Curlewis ◽  
GM Stone
Keyword(s):  
Luteal Phase ◽  
Oestrous Cycle ◽  
Vaginal Smear ◽  
Early Age ◽  
Corpora Lutea ◽  
Gestation Length ◽  
Left And Right ◽  
The Mean ◽  
Breeding Seasons ◽  
Effect Of Age

Basic reproductive data were collected from a group of wild-caught brushtail possums during three breeding seasons. The mean (�SE) oestrous cycle length, gestation length and interval from removal of pouch young (RPY) to oestrus were 26.3 � 1.46 (n = 39), 17.1 � 0.14 (n = 21) and 9.0 � 0.46 (n = 41) days respectively, agreeing closely with previously published reports. Sperm were first observed in the vaginal smear on days 0 and 1 of the cycle in mated animals, but 27% of matings did not result in the production of a neonate. There was no effect of age of pouch young on the interval between RPY and oestrus but the incidence of mating was greater when pouch young were removed at an early age. In 25 animals examined during an oestrous cycle corpora lutea or Graafian follicles were unequally distributed between left and right ovaries. During the course of the study, four animals were identified in which oestrus was not followed by a luteal phase.

THE SHEEP CORPUS LUTEUM SECRETES INHIBIN

1988 ◽  
Vol 116 (3) ◽  
pp. R3-R5 ◽  
Author(s):  
C. G. Tsonis ◽  
D. T. Baird ◽  
B. K. Campbell ◽  
R. Leask ◽  
R. J. Scaramuzzi
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Venous Blood ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Luteal Tissue ◽  
Two Stages

ABSTRACT An experiment was performed in 20 Merino ewes in which ovarian venous blood was collected by venepuncture at surgery and at two stages of the oestrous cycle. The ovarian venous concentrations of inhibin, oestradiol-17β and progesterone were determined. The results demonstrate that during the luteal phase of the oestrous cycle the ovarian venous blood draining an ovary containing luteal tissue contains significantly more inhibin bioactivity than ovarian venous blood from an ovary not containing luteal tissue. During the follicular phase the concentration of inhibin bioactivity in ovarian venous blood was reduced compared with the luteal phase. From this data we conclude that the sheep corpus luteum secretes inhibin bioactivity into the ovarian venous blood.

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