scholarly journals Role of PGF2alpha and oxytocin in parturition in the brushtail possum (Trichosurus vulpecula)

Reproduction ◽  
2002 ◽  
pp. 429-434 ◽  
Author(s):  
C Veitch ◽  
L Brown ◽  
C Sernia ◽  
RT Gemmell
Keyword(s):  
Corpus Luteum ◽  
Uterine Contraction ◽  
Adrenal Glands ◽  
Tammar Wallaby ◽  
Brushtail Possum ◽  
Uterine Contractions ◽  
Prostaglandin F ◽  
Birth Position

Maturation of the fetal pituitary and adrenal glands allows the secretion of cortisol, which in turn leads to an increase in prostaglandin and mesotocin production. The production of prostaglandin and mesotocin results in an increase in uterine contractions and initiates birth in marsupials. The major metabolite of PGF(2alpha), 13,14-dihydro-15-keto-prostaglandin F(2alpha) (PGFM), has been found in the plasma of the possum at the time of birth and administration of PGF(2alpha) to female possums induced the adoption of the birth position. Evidence that mesotocin is an integral hormone of birth in the tammar wallaby indicates that both PGF(2alpha) and mesotocin or oxytocin are required for marsupial birth. The presence of PGF(2alpha) receptors in the uterus and corpus luteum of the possum, and the in vitro uterine responsiveness to PGF(2alpha) or oxytocin, were examined. PGF(2alpha) receptors were not observed in possum uteri and the inability of PGF(2alpha) to cause contractions indicates that PGF(2alpha) is not involved directly in contraction of the uterus at parturition. The presence of oxytocin and mesotocin receptors in the uterus of possoms and the ability of oxytocin to induce uterine contraction in vitro supports the view that mesotocin is required for expulsion of the young from the uterus. Low numbers of PGF(2alpha) receptors were found in the possum corpus luteum at birth, indicating an involvement of PGF(2alpha) in regression of the corpus luteum.

scholarly journals The role of IGFs in the regulation of ovarian follicular growth in the brushtail possum (Trichosurus vulpecula)

Reproduction ◽  
2010 ◽  
Vol 140 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Jennifer L Juengel ◽  
Lisa J Haydon ◽  
Brigitta Mester ◽  
Brian P Thomson ◽  
Michael Beaumont ◽  
...  
Keyword(s):  
Granulosa Cell ◽  
Granulosa Cells ◽  
Cell Function ◽  
Antral Follicle ◽  
Brushtail Possum ◽  
Follicular Growth ◽  
Theca Cells ◽  
Ovarian Follicular Growth

IGFs are known to be key regulators of ovarian follicular growth in eutherian mammals, but little is known regarding their role in marsupials. To better understand the potential role of IGFs in the regulation of follicular growth in marsupials, expression of mRNAs encoding IGF1, IGF2, IGF1R, IGF-binding protein 2 (IGFBP2), IGFBP4 and IGFBP5 was localized by in situ hybridization in developing ovarian follicles of the brushtail possum. In addition, the effects of IGF1 and IGF2 on granulosa cell function were tested in vitro. Both granulosa and theca cells synthesize IGF mRNAs, with the theca expressing IGF1 mRNA and granulosa cell expressing IGF2 mRNA. Oocytes and granulosa cells express IGF1R. Granulosa and theca cells expressed IGFBP mRNAs, although the pattern of expression differed between the BPs. IGFBP5 mRNA was differentially expressed as the follicles developed with granulosa cells of antral follicles no longer expressing IGFBP5 mRNA, suggesting an increased IGF bioavailability in the antral follicle. The IGFBP protease, PAPPA mRNA, was also expressed in granulosa cells of growing follicles. Both IGF1 and IGF2 stimulated thymidine incorporation but had no effect on progesterone production. Thus, IGF may be an important regulator of ovarian follicular development in marsupials as has been shown in eutherian mammals.

scholarly journals HIF-1α Activation Promotes Luteolysis by Enhancing ROS Levels in the Corpus Luteum of Pseudopregnant Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zonghao Tang ◽  
Jiajie Chen ◽  
Zhenghong Zhang ◽  
Jingjing Bi ◽  
Renfeng Xu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Corpus Luteum ◽  
Cell Apoptosis ◽  
In Vitro Study ◽  
Luteal Cell ◽  
Independent Manner ◽  
Luteal Regression ◽  
Luteal Cells

The increase of oxidative stress is one of the important characteristics of mammalian luteal regression. Previous investigations have revealed the essential role of reactive oxygen species (ROS) in luteal cell death during luteolysis, while it is unknown how ROS is regulated in this process. Considering the decrease of blood flow and increase of PGF2α during luteolysis, we hypothesized that the HIF-1α pathway may be involved in the regulation of ROS in the luteal cell of the late corpus luteum (CL). Here, by using a pseudopregnant rat model, we showed that the level of both HIF-1α and its downstream BNIP3 was increased during luteal regression. Consistently, we observed the increase of autophagy level during luteolysis, which is regulated in a Beclin1-independent manner. Comparing with early (Day 7 of pseudopregnancy) and middle CL (Day 14), the level of ROS was significantly increased in late CL, indicating the contribution of oxidative stress in luteolysis. Inhibition of HIF-1α by echinomycin (Ech), a potent HIF-1α inhibitor, ameliorated the upregulation of BNIP3 and NIX, as well as the induction of autophagy and the accumulation of ROS in luteal cells on Day 21 of pseudopregnancy. Morphologically, Ech treatment delayed the atrophy of the luteal structure at the late-luteal stage. An in vitro study indicated that inhibition of HIF-1α can also attenuate PGF2α-induced ROS and luteal cell apoptosis. Furthermore, the decrease of cell apoptosis can also be observed by ROS inhibition under PGF2α treatment. Taken together, our results indicated that HIF-1α signaling is involved in the regression of CL by modulating ROS production via orchestrating autophagy. Inhibition of HIF-1α could obviously hamper the apoptosis of luteal cells and the process of luteal regression.

The role of Acacia in the diets of Australian marsupials ? A review.

2003 ◽  
Vol 25 (2) ◽  
pp. 121 ◽  
Author(s):  
NA Irlbeck ◽  
ID Hume
Keyword(s):  
Tammar Wallaby ◽  
Energy Budgets ◽  
Brushtail Possum ◽  
Seasonal Component ◽  
Acacia Gum ◽  
Form Part ◽  
Dry Seasons ◽  
Petaurus Breviceps ◽  
Quantitative Contributions

Many of the 600 species of Acacia found in Australia form part of the diet of several groups of marsupials. Acacia foliage is generally high in tannins but is consumed by several folivorous possums and by some macropods (kangaroos and wallabies), but the macropods eat it mainly as dry leaf litter during times of food shortage (in dry seasons and drought). Acacia gum is an important diet component of two omnivorous possums (Petaurus breviceps, Gymnobelidius leadbeateri) and, to a lesser extent, two rat-kangaroos (Bettongia sp.). Acacia seeds are consumed by marsupials to a limited extent, but are an important seasonal component of the diet of the mountain brushtail possum (Trichosurus cunninghami), and possibly the tammar wallaby (Macropus eugenii) on Kangaroo Island. Likewise, Acacia arils (lipid-rich appendages to the seeds of some species) are an important seasonal component of the diet of the mahogany glider (Petaurus gracilis). Acacia pollen and nectar are consumed by several omnivorous possums (e.g., Petaurus norfolcensis) as well as by at least one species of rock-wallaby (Petrogale sp.), but the quantitative contributions made by these floral products to the protein and energy budgets of the consumers have been difficult to determine. Thus several parts of the Acacia plant are food resources for one or more groups of marsupials, but the contribution of the genus to marsupial nutrition is often overlooked.

scholarly journals Opposing Roles of Leptin and Ghrelin in the Equine Corpus Luteum Regulation: AnIn VitroStudy

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
António Galvão ◽  
Angela Tramontano ◽  
Maria Rosa Rebordão ◽  
Ana Amaral ◽  
Pedro Pinto Bravo ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Reproductive Function ◽  
Secretory Activity ◽  
Dependent Manner ◽  
Angiogenic Activity ◽  
Metabolic Hormones ◽  
Protein Levels ◽  
Dose Dependent

Metabolic hormones have been associated with reproductive function modulation. Thus, the aim of this study was: (i) to characterize the immunolocalization, mRNA and protein levels of leptin (LEP), Ghrelin (GHR) and respective receptors LEPR and Ghr-R1A, throughout luteal phase; and (ii) to evaluate the role of LEP and GHR on progesterone (P4), prostaglandin (PG) E2and PGF2α, nitric oxide (nitrite), tumor necrosis factor-α(TNF); macrophage migration inhibitory factor (MIF) secretion, and on angiogenic activity (BAEC proliferation), in equine corpus luteum (CL) from early and mid-luteal stages. LEPR expression was decreased in late CL, while GHR/Ghr-R1A system was increased in the same stage. Regarding secretory activity, GHR decreased P4in early CL, but increased PGF2α, nitrite and TNF in mid CL. Conversely, LEP increased P4, PGE2, angiogenic activity, MIF, TNF and nitrite during early CL, in a dose-dependent manner. Thein vitroeffect of LEP on secretory activity was reverted by GHR, when both factors acted together. The present results evidence the presence of LEP and GHR systems in the equine CL. Moreover, we suggest that LEP and GHR play opposing roles in equine CL regulation, with LEP supporting luteal establishment and GHR promoting luteal regression. Finally, a dose-dependent luteotrophic effect of LEP was demonstrated.

Effect of brain monoamines on the secretion of adrenocorticotrophic hormone

1982 ◽  
Vol 101 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Alka Amar ◽  
S. Mandal ◽  
A. K. Sanyal
Keyword(s):  
Dopaminergic Neurons ◽  
Adrenal Glands ◽  
Plasma Corticosterone ◽  
Albino Rats ◽  
Adrenocorticotrophic Hormone ◽  
Brain Monoamines ◽  
Acth Secretion ◽  
Acute Increase

Abstract. The role of brain monoamines (5-HT, NA and DA) in the secretion of adrenocorticotrophic hormone (ACTH) was studied in view of contradictory reports. Plasma corticosterone levels and the rate of synthesis of corticosterone in vitro by the adrenal gland were estimated in albino rats and have been taken as the index of ACTH activity. These estimations were done in unstressed and stressed, and in untreated and treated rats. Drugs were administered intracerebroventricularly to the rats to cause selective degeneration of tryptaminergic, noradrenergic or dopaminergic neurons. The results show that plasma corticosterone levels and the rate of synthesis of corticosterone were significantly decreased after selective degeneration of tryptaminergic neurons in unstressed rats. After selective degeneration of either tryptaminergic or noradrenergic neurons, the acute increase in the plasma corticosterone levels and rate of synthesis of corticosterone in vitro by adrenal glands in stressed rats were significantly inhibited. These results have been interpreted to suggest that the central tonic control on adrenal glands may be 5-HT mediated and that during stress ACTH secretion may be both 5-HT and NA mediated. DA does not seem to have significant role in the regulation of ACTH secretion.

Daily prolactin pulse inhibits the corpus luteum during lactational quiescence in the marsupial, Macropus eugenii

2013 ◽  
Vol 25 (2) ◽  
pp. 456 ◽  
Author(s):  
L. A. Hinds ◽  
C. H. Tyndale-Biscoe
Keyword(s):  
Corpus Luteum ◽  
Tammar Wallaby ◽  
Marked Contrast ◽  
Previous Conclusion ◽  
Macropus Eugenii ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Progesterone Synthesis ◽  
Rate Limiting

The corpus luteum (CL) of the tammar wallaby is inhibited by prolactin during lactation and seasonal quiescence. In seasonal quiescence a daily transient pulse of prolactin (PRL) of less than 2 h duration is sufficient to maintain inhibition. We investigated whether the same inhibition applies in lactation and, if so, how. Our results show that inhibition of the CL during lactation is maintained by a transient pulse of prolactin once a day. They also show that the minimum time without a PRL pulse for the CL to escape inhibition is more than 48 h and less than 72 h. Nevertheless, some animals had a longer refractory period than 72 h, which was reflected in a longer interval to the progesterone peak and birth. These results support the previous conclusion that PRL exercises its effect on a rate-limiting step in progesterone synthesis and secretion rate from the CL, which precedes any increase in its mass. Therefore, we conclude that the role of PRL is to act as a luteostatic agent, an effect that is in marked contrast to its luteotrophic effect in many eutherian species, including rodents.

THE CONCENTRATION OF PROSTAGLANDIN F2α IN MATERNAL PLASMA, FOETAL PLASMA AND AMNIOTIC FLUID DURING PREGNANCY IN WOMEN

1975 ◽  
Vol 79 (3) ◽  
pp. 589-597 ◽  
Author(s):  
D. A. Johnson ◽  
P. A. Manning ◽  
J. F. Hennam ◽  
J. R. Newton ◽  
W. P. Collins
Keyword(s):  
Amniotic Fluid ◽  
Prostaglandin F2α ◽  
Late Pregnancy ◽  
Maternal Plasma ◽  
Uterine Contractions ◽  
Prostaglandin F ◽  
Serial Samples ◽  
Considerable Individual Variation ◽  
Venous Plasma

ABSTRACT The concentration of prostaglandin F2α has been determined in serial samples of peripheral venous plasma from women at defined times during labour, and studied in detail throughout two consecutive uterine contractions. In addition, the same compound has been measured in single samples of uterine venous plasma, cord venous plasma, and amniotic fluid in groups of patients during early and late pregnancy, labour and at delivery of the baby. The results from the analysis of peripheral venous plasma show that there is considerable individual variation in the concentration of prostaglandin F2α during labour (mean ± sd, 33.1 ± 11.6 pg/ml). However, it is not possible to establish a definite correlation with either the latent or accelerated phases or with the time of delivery. Furthermore, there is no apparent temporal relationship between the concentrations in peripheral venous plasma and the contractile state of the uterus as assessed by external tocography. In early pregnancy (16th to 20th week) the concentration of prostaglandin F2α (pg/ml, mean ± sd) in peripheral venous plasma is 26.3 ± 4.3 and in amniotic fluid 32.7 ± 26.5. At the 36th week to the start of labour the corresponding values are 27.1 ± 8.1 and 110.0 ± 73.8. At the same time the levels in cord plasma and uterine venous plasma are 100.4 ± 74.9 and 87.9 ± 55.0 respectively. During labour there is a significant increase (P < 0.005, Student's t-test) in the concentration in amniotic fluid (335.1 ± 171.0). The results are discussed in relation to the possible role of prostaglandin F2α in the process of parturition.

STEROID AND PROSTAGLANDIN SECRETION BY THE CORPUS LUTEUM, ENDOMETRIUM AND EMBRYOS OF CYCLIC AND PREGNANT PIGS

1979 ◽  
Vol 82 (3) ◽  
pp. 425-428 ◽  
Author(s):  
J. WATSON ◽  
C. E. PATEK
Keyword(s):  
Corpus Luteum ◽  
Late Stage ◽  
Oestrous Cycle ◽  
Corpora Lutea ◽  
Reproductive Tissues ◽  
Prostaglandin F

Prostaglandin F2α (PGF2α) secreted by the reproductive tissues of the pig in vitro was measured and it was found that the levels secreted by the corpus luteum and endometrium of early pregnant sows were significantly lower than those secreted by tissues during the late stage of the oestrous cycle. They were, however, comparable to levels secreted by tissues from the mid-stage of the oestrous cycle. Embryos also secreted significant amounts of PGF2α. Secretion of progesterone and oestradiol by the corpora lutea of both cyclic and pregnant pigs fell within accepted limits but embryos were also found to secrete significant amounts of oestradiol. The results suggest that luteal maintenance in the early pregnant pig is unlikely to be directly due to reduced synthesis of PGF2α.

Release of galanin from isolated perfused porcine adrenal glands: role of splanchnic nerves

1991 ◽  
Vol 261 (1) ◽  
pp. E31-E40 ◽  
Author(s):  
J. J. Holst ◽  
M. Ehrhart-Bornstein ◽  
T. Messell ◽  
S. S. Poulsen ◽  
H. Harling
Keyword(s):  
Nerve Stimulation ◽  
Adrenal Glands ◽  
Splanchnic Nerve ◽  
High Concentration ◽  
Vitro Model ◽  
Arterial Plasma ◽  
Regulatory Functions ◽  
Splanchnic Nerve Stimulation

We found a high concentration of galanin in extracts of porcine adrenal glands (114 pmol/g). By immunohistochemistry, galanin was localized to groups of medullary cells previously shown to produce norepinephrine. To study mechanisms for the release of galanin, we developed the following in vitro model: isolated perfused porcine adrenals with intact splanchnic nerve supply. When the nerves were electrically stimulated, epinephrine and norepinephrine secretion increased 276- and 291-fold, respectively, and galanin release increased up to 1,300-fold. Acetylcholine at 10(-6) M stimulated galanin release, and hexamethonium almost abolished the response to nerve stimulation. Galanin infusions had no effect on epinephrine and norepinephrine secretion in concentrations of 10(-8) and 10(-7) M, but increased both cortisol and aldosterone secretion (P less than 0.05). Splanchnic nerve stimulation in anesthetized pigs increased the concentration of galanin in the caval vein but not in arterial plasma. It is concluded that galanin, coreleased with catecholamines from the adrenal glands, may have endocrine functions but that galanin may also have local regulatory functions in the adrenals.

Pellet-freezing spermatozoa of two marsupials: the tammar wallaby, Macropus eugenii, and the brushtail possum, Trichosurus vulpecula

1996 ◽  
Vol 8 (4) ◽  
pp. 681 ◽  
Author(s):  
FC Molinia ◽  
JC Rodger
Keyword(s):  
Room Temperature ◽  
Tammar Wallaby ◽  
Brushtail Possum ◽  
Vitro Fertilization ◽  
Macropus Eugenii ◽  
Progressive Motility ◽  
Viable Population ◽  
Phosphate Buffered Saline ◽  
Breeding Techniques

A protocol was developed for pellet-freezing spermatozoa of the tammar wallaby and the brushtail possum. Seren was collected by electro-ejaculation and wallaby spermatozoa were washed by 'swim-up' into phosphate-buffered saline (PBS), whereas possum spermatozoa were not washed. Wallaby spermatozoa were screened for toxicity in diluents containing a range of cryoprotectants (0-10%): dimethyl sulfoxide (DMSO), ethylene glycol and propanediol. Possum spermatozoa were tolerant of diluents containing 17.5% glycerol. Wallaby and possum spermatozoa were diluted 1:1 with the most promising cryoprotective diluents (final concentrations in PBS: possum, 17.5% glycerol; wallaby, 7.5% glycerol + 10% DMSO) and, after 5 min equilibration at room temperature, were pellet-frozen. Pellets were thawed (35 degrees C) and wallaby spermatozoa were washed by centrifugation (200 g for 5 min) and resuspended in PBS to minimize cryoprotectant toxicity. A high proportion of possum spermatozoa was recovered after freezing (67.5%), having good progressive motility (3.6 on a 0-5 scale). The progressive motility of frozen-thawed wallaby spermatozoa was also high (3.0), but only 10% of motile spermatozoa were recovered. The pellet-freezing method in conjunction with the post-thaw washing procedure (wallaby) may produce a viable population of cryopreserved marsupial spermatozoa suitable for use in assisted-breeding techniques such as in vitro fertilization and artificial insemination.

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