Pregnancy in the lactating pigmy possum, Cercartetus concinnus

1967 ◽  
Vol 15 (4) ◽  
pp. 673 ◽  
Author(s):  
MJ Clarke
Keyword(s):  
Connective Tissue ◽  
Post Partum ◽  
Circumstantial Evidence ◽  
Corpora Lutea ◽  
Embryonic Diapause ◽  
Luteal Regression ◽  
Pregnant Females ◽  
Pass Through

The reproductive tracts of seven Cercartetus concinnus with pouch young were examined. One female had recently given birth, four were pregnant, and two were in anoestrus. The post-partum female was near oestrus. The ovaries contained corpora lutea and large follicles, and luteal regression was occurring in the uteri. Ovaries of pregnant females contained old corpora lutea and corpora lutea of pregnancy. Blastocysts recovered from the uteri increased in size with age of the pouch young. Corpora lutea of pregnancy out-numbered blastocysts in many females, and blastocysts often out-numbered teats. Ovaries of anoestrous females contained only old corpora lutea. During birth the young pass through a cleft in the connective tissue between the posterior end of the vaginal culs-de-sac and the posterior vaginal sinus. This cleft, the pseudovaginal canal, closes after parturition. The observation that embryos of C. concinnus do not enter diapause contrasts with conclusions previously drawn from circumstantial evidence that the pigmy possum resembled several species of Macropodidae in undergoing embryonic diapause.

EFFECTS OF INHIBITING PROLACTIN SECRETION ON THE MAINTENANCE OF EMBRYONIC DIAPAUSE IN THE SUCKLING RAT

1981 ◽  
Vol 88 (2) ◽  
pp. 197-203 ◽  
Author(s):  
R. G. GOSDEN ◽  
J. A. RUSSELL ◽  
J. CLARKE ◽  
I. PIPER ◽  
A. S. McNEILLY
Keyword(s):  
Post Partum ◽  
Prolactin Secretion ◽  
Serum Prolactin ◽  
Embryonic Diapause ◽  
Luteal Regression ◽  
Embryonic Resorption

Treatment of rats with bromocriptine between days 5 and 8 after the post-partum mating resulted in suppression of serum prolactin levels and caused luteal regression. Although this treatment led to embryonic resorption when suckling was prevented by removing litters soon after birth, the diapausing embryos of animals nursing a litter of eight pups were unaffected by the treatment. These results suggest that the high levels of prolactin and progesterone in the circulation during lactation are not responsible for maintenance of the diapausing state.

The Reproductive Rate of the Hopping-Mouse Notomys Alexis and Its Ecological Significance.

1979 ◽  
Vol 27 (2) ◽  
pp. 177 ◽  
Author(s):  
WG Breed
Keyword(s):  
Post Partum ◽  
Cumulus Cells ◽  
Reproductive Rate ◽  
Seminiferous Tubules ◽  
Corpora Lutea ◽  
Fallopian Tubes ◽  
Ecological Significance ◽  
High Population Density ◽  
Young Females ◽  
Pregnant Females

In the male hopping-mouse, spermatozoa first appeared in seminiferous tubules on day 60 and were present in the epididymis a few days later; ventral prostates markedly increased in weight between days 56 and 60. Some females had large Graafian follicles, stimulated uteri and perforate vaginae on day 40; corpora lutea were first observed on day 44, but most females did not spontaneously ovulate until after day 54. Gestation in post-partum mated, non-suckling females lasted about 32 days, with implantation on day 7 or 8. When four or more young were suckling, gestation increased to 39 days (mean); implantation took place between days 11-13 and 14-17 when there were either three or four, or five, suckling young respectively. From one to three unfertilized oocytes surrounded by cumulus cells were found in the Fallopian tubes between days 7 and 17 in some pregnant females. Post partum, the most common ovulation rate and litter size was 4; 72% of these litters fully survived to weaning; 10-15% of litters were of five or six young and nearly half of these fully survived to weaning; in the natural environment litters were of four or five young. Without post-partum mating and without suckling young, females had ovulated spontaneously by days 9-11. Significantly fewer females suckling from four to six young had oocytes at this time, but the percentage had increased by days 15-18. This indicates a delay, but not prevention, of spontaneous ovulation during lactation. Field-caught females from the southern Northern Territory were reproductively inactive on three out of four occasions. The fourth time, when there had been > 50 mm of rain in the preceding few weeks, all adult females caught had corpora lutea and some were pregnant. Greatest ovarian inhibition coincided with high population density. When compared to data for small northern temperate-zone rodents, most of the above reproductive parameters do not indicate a high reproductive rate, but data for closely related, apparently non-cyclic, Australian species appear to be similar except for, possibly, age of puberty and spontaneous ovulation during lactation. The significance of these results to r-strategy in this species is discussed.

HEMMUNG VON TESTOSTERONABHÄNGIGEN DIFFERENZIERUNGSVORGÄNGEN DER MÄNNLICHEN RATTE NACH DER GEBURT

1967 ◽  
Vol 54 (2) ◽  
pp. 227-240 ◽  
Author(s):  
F. Neumann ◽  
J. D. Hahn ◽  
M. Kramer
Keyword(s):  
Sexual Behaviour ◽  
Cyproterone Acetate ◽  
Post Partum ◽  
Sexual Attitude ◽  
Normal Male ◽  
Corpora Lutea ◽  
List Type ◽  
Newborn Rats ◽  
Neonatal Treatment ◽  
Triangular Shape

ABSTRACT Male newborn rats were injected with 2 mg of an antiandrogen (1,2α-methylene-6-chloro-pregna-4,6-dien-17α-ol-3,20-dione-17α-acetate = cyproterone acetate) daily from their 1st to their 14th day of life. The following effects of this treatment were observed in these animals after onset of sexual maturity: 84% of the animals are unable to reproduce. Penis: the frenulum is broadened to a lamina of triangular shape, which almost completely prevents the preputium from being pushed back. These males show a rather insufficient male sexual behaviour towards females in oestrus. After castration and ovar implantation, some of the treated animals show true corpora lutea and at attempts of cohabitation partially female sexual behaviour towards normal male animals. From these results it can be concluded, that differentiation of the penis is not completed at the time of birth. The infertility of the animals may be caused by the penile changes (difficulties with intromission) as well as by the aimless sexual behaviour. This aimless sexual behaviour, the ability to produce true corpora lutea and finally their partially female sexual attitude under the influence of the hormones from the implanted ovaries led to the conclusion, that the above described neonatal treatment apparently inhibited testosterone-depending post partum developments of sexual differentiation in hypothalamic centers.

Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus)

Reproduction ◽  
2000 ◽  
pp. 49-57 ◽  
Author(s):  
SD Johnston ◽  
MR McGowan ◽  
P O'Callaghan ◽  
R Cox ◽  
V Nicolson
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Plasma Concentrations ◽  
External Genitalia ◽  
Oestrous Cycle ◽  
Phascolarctos Cinereus ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
The Mean ◽  
High Concentrations

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

scholarly journals The immunohistochemical presence and distribution of ghrelin, apelin and their receptors in dog ovaries

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Carolina Pirino ◽  
Margherita Maranesi ◽  
Angela Polisca ◽  
Alessandro Troisi ◽  
Cecilia Dall'Aglio
Keyword(s):  
Connective Tissue ◽  
Infectious Diseases ◽  
Positive Reaction ◽  
Corpora Lutea ◽  
Small Arteries ◽  
Luteal Cells ◽  
Peripheral Organs ◽  
Immunohistochemical Techniques

The activity of ghrelin, apelin and their receptors has been correlated to the control of some infectious diseases, besides the hypothesis of their role in the control of some peripheral organs, among which ovaries. The aim of the present work was to highlight the presence and distribution of ghrelin, apelin and cognate receptors in the ovaries of pregnant bitches, by means of immunohistochemical techniques. Apelin, its receptor and the receptor of ghrelin were highlighted in the corpora lutea, with a particular localization in the cytoplasm of some luteal cells. Instead, a positive reaction for ghrelin was evident in the walls of small arteries in the connective tissue. These results allowed us to hypothesize that these molecules intervene in the control of ovaries in pregnant bitches, suggesting autocrine/paracrine mechanisms of regulation.

Reproductive Ecology of The Allied Rock-wallaby, Petrogale assimilis.

1996 ◽  
Vol 19 (2) ◽  
pp. 209
Author(s):  
R. Delaney
Keyword(s):  
Life History ◽  
Sex Ratio ◽  
Sexual Maturity ◽  
Post Partum ◽  
Reproductive Ecology ◽  
Oestrous Cycle ◽  
Embryonic Diapause ◽  
Minimum Age

Petrogale assimilis has a typical life history and reproductive ecology for a macropodid of its size. Both sexes are capable of reproducing continuously; gestation is about the same length as the oestrous cycle (approximately one month); a single young is born and, a post-partum oestrus and embryonic diapause probably occurs. The sex ratio of young is unbiased. Pouch young remain permanently attached to the teat until 110 - 143 days (n=11). Permanent exit from the pouch occurs at 180 - 231 days (mean=201 days, n=25), and weaning occurs between 267 - 387 days (n=5). Sexual maturity occurs at a minimum age of 17.5 months in females and 23 months in males.

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.

Reproductive function in average and high yielding dairy cows

2001 ◽  
Vol 26 (2) ◽  
pp. 495-498 ◽  
Author(s):  
Victoria J. Taylor ◽  
Andrew J. Hattan ◽  
Emma C.L. Bleach ◽  
David E. Beever ◽  
D. Claire Wathes
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Post Partum ◽  
Reproductive Function ◽  
Reproductive Activity ◽  
Corpora Lutea ◽  
Genetic Merit ◽  
Standard Management ◽  
Service Conception ◽  
The Difference

AbstractThe resumption of reproductive activity in the early post partum period and the subsequent fertility of dairy cows are of considerable practical and economic importance to the producer. Regular milk progesterone analysis was used in this study to monitor the re-establishment of reproductive cyclicity in animals of average (AGM, n=20) and high genetic merit (HGM, n=28) kept under standard management conditions. The profiles obtained were then characterised into normal and four different types of abnormal activity. Resumption of cycles occurred significantly later in the higher yielding cows than in those of average genetic merit (23 ±2.3 days in HGM cows and 15 ± 1.6 days in AGM cows; P=0.0089). There was a significant increase in the amount of abnormal cycles encountered in the high genetic merit animals compared with average yielding animals (61% and 30% respectively; χ2 test, P=0.045); in particular, the delayed occurrence of ovulation post partum (11% vs 0%) and an increased incidence of persistent corpora lutea (32% vs 20%). For high genetic merit animals, the incidence of abnormal cycles was associated with increased peak milkyields (abnormal cycles: peak milk yield 54.7 ± 1.11 kg/day; normal cycles: peak milk yield 46.4 ± 1.35 kg/day, P=0.002). This relationship was not apparent in average genetic merit animals. First service conception rates were 50% (9/18) for AGM cows and 38% (10/26) for HGM cows (χ2 test, n.s.). The calving to conception interval was 98 ± 9.7 days for AGM animals (n=l7) and 105 ± 9.1 days for HGMs (n=24) (t-test, n.s.). In conclusion, this study confirms that high genetic merit dairy cows have compromised reproductive function in terms of a delayed resumption of cyclicity and an increased incidence of abnormal progesterone cycles, which was associated with higher peak milk yields. There was also a reduced first service conception rate in high yielders although the difference was not significant with this group size.

Effects of calcium salts of fatty acids on follicular characteristics and several blood parameters in two fat-tailed sheep breeds

2002 ◽  
Vol 2002 ◽  
pp. 131-131
Author(s):  
M. J. Zamiri ◽  
E. Rowghani ◽  
S. M. Ghoreishi
Keyword(s):  
Fatty Acids ◽  
Plasma Cholesterol ◽  
Post Partum ◽  
Reproductive Function ◽  
Blood Parameters ◽  
Dietary Lipid ◽  
Ovarian Activity ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Sheep Breeds

There is substantial evidence that the increased consumption of fat by dairy cattle can result in an increase in the number ovarian follicles, and the number and size of corpora lutea; it also stimulates post-partum ovarian activity and improve pregnancy rate. Increased dietary lipid also increases plasma cholesterol and progesterone, and the supply of lipoproteins which play significant roles in regulating ovarian steroidogenesis (Willimas, 1996). In contrast to cattle, there are few observations on the effects of dietary lipid on reproductive function in sheep. Intravascular infusion of lipid into ewes stimulated progesterone and prostaglandin synthesis (Burke et al., 1996), and dietary supplementation of calcium soaps of fatty acids enhanced luteal function (Kuran et al., 1999). Calcium soaps of fatty acids have been manufactured in Iran in recent years and sold under the trade name of Megalac. The aim of the present experiment was to study the effects of this protected fat on follicular number and luteal activity in two fat-tailed sheep breeds.

THE RELATIONSHIP BETWEEN THE UTERUS AND OVARIES DURING EARLY PREGNANCY IN THE GUINEA-PIG

1972 ◽  
Vol 53 (2) ◽  
pp. 295-301 ◽  
Author(s):  
F. R. BLATCHLEY ◽  
B. T. DONOVAN
Keyword(s):  
Guinea Pig ◽  
Early Pregnancy ◽  
Guinea Pigs ◽  
Uterine Horn ◽  
Vaginal Smear ◽  
Corpora Lutea ◽  
Luteal Regression ◽  
Experimental Animals ◽  
Decidual Reaction ◽  
The Relationship

SUMMARY In mated guinea-pigs one uterine horn was rendered sterile by ligation of the oviduct 2 or 3 days after finding spermatozoa in the vaginal smear. Two glass beads were inserted into the sterile horn on each of days 3–12 and on day 14 in experimental animals but not in controls. At autopsy on day 20 large corpora lutea were present in both ovaries of the control animals. The presence of beads that had been introduced on days 3 and 4 and on days 10–14 resulted in marked regression of the corpora lutea in the adjacent ovary, in the absence of a decidual reaction in the uterus, while luteal enlargement typical of pregnancy occurred in the contralateral ovary. Beads inserted on days 5–8 caused decidualization in the sterile horn but did not induce premature luteal regression in the ipsilateral ovary.

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