The inability of some synthetic progestagens to maintain pregnancy in the mare

McKinnon, A. O.; Lescun, Timothy B.; Walker, J; Vasey, J. R.; Allen, W. R.

doi:10.2746/042516400777612035

Cited by 43 publications

(29 citation statements)

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“…Low serum progesterone levels also have been associated with early pregnancy loss in mares [Bergfeldt et al, 1992]. Although luteal insufficiency has not been proven to be a primary cause of pregnancy loss [Ginther, 1995], the oral progesterone supplement altrenogest is commonly prescribed in suspected cases and appears to be the only form of progesterone associated with sustaining pregnancy [McKinnon et al, 2000]. Furthermore, altrenogest is apparently safe Squires et al, 1983] and does not effect the fertility of resulting offspring [Naden et al, 1990].…”

Section: Introductionmentioning

confidence: 99%

Endocrine and ultrasonographic characterization of a successful pregnancy in a Sumatran rhinoceros (Dicerorhinus sumatrensis) supplemented with a synthetic progestin

et al. 2004

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A Sumatran rhinoceros with a history of early pregnancy loss was supplemented with a synthetic progestin, altrenogest (Regu-Mate s ), and delivered a healthy, full-term calf 475 days after mating. Serum hormone concentrations were measured throughout gestation, and ultrasonography was used to monitor embryo/fetal growth and viability. The embryonic vesicle growth curve was characterized by three phases: rapid expansion, plateau, and a final rapid expansion, and was similar to that in the domestic horse. Fetal sex was determined by ultrasound on day 73 of gestation. After day 80 of gestation, transabdominal examinations were more useful than rectal examinations for imaging the fetus. Serum progesterone concentrations remained at luteal levels (1.570.5 ng/ml) for the first 2 months of pregnancy, and then they gradually increased. However, progesterone decreased almost to luteal levels during the fifth month before it increased again, and eventually reached peak concentrations (13.371.9 ng/ml) shortly before parturition. Relaxin concentrations remained basal (r0.5 ng/ml) for the first half of the pregnancy, increased to 2.771.2 ng/ml and stabilized until 2 weeks before parturition, when relaxin spiked to unusually high concentrations (800-1300 ng/ml). Prolactin concentrations were at baseline (7.271.7 ng/ml) throughout most of the gestation, but rose markedly 2 weeks before parturition, reaching concentrations as high as 75 ng/ml. Attempts to measure serum estrogen concentrations were unsuccessful. These data represent the first attempt to characterize pregnancy in the critically endangered Sumatran rhinoceros, a species that heretofore had not successfully reproduced in captivity for 112 years.

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Section: Introductionmentioning

confidence: 99%

Endocrine and ultrasonographic characterization of a successful pregnancy in a Sumatran rhinoceros (Dicerorhinus sumatrensis) supplemented with a synthetic progestin

et al. 2004

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“…Repeated embryonic loss attributable to a failure of maternal recognition of pregnancy can be prevented with supplemental progestogens such as altrenogest. A number of synthetic progestogens, including medroxyprogesterone, norgestomet and megestrol acetate, were unable to maintain pregnancy (McKinnon et al 2000). To ensure pregnancy maintenance, exogenous progestogen therapy should be continued through the first 4 months of gestation, until the placenta can be considered to provide adequate progestogens for pregnancy support.…”

Section: Discussionmentioning

confidence: 99%

Pregnancy loss during the embryonic period

Paccamonti¹,

Carnevale²

2008

PHK

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“…Different binding responses were seen depending on the tracer used. We used 2000 units of fluorescence intensity in 10 mM PBS, which is equivalent to 22.6 mM as fluorescein (extinction coefficient: 8.78ϫ10 4 …”

Section: Synthesis Of Fluorescence Labeledmentioning

confidence: 99%

“…The tracers were stored in the dark at 4°C. The concentration of tracer was estimated spectrophotometrically at 492 nm using an extinction coefficient of 8.78ϫ10 4 …”

Section: Instruments and Chemicalsmentioning

confidence: 99%

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Development of One-Step Fluorescence Polarization Immunoassay for Progesterone.

Hong

Choi

2002

Biological & Pharmaceutical Bulletin

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Progesterone has been known to play a significant role in the facilitation of implantation and in the maintenance of pregnancy. This critical influence of progesterone is most likely due to its well-known ability to inhibit uterine contractility and to suppress the immune response to the fetus. 1,2) During pregnancy as well as the luteal phase of the menstrual cycle after ovulation, progesterone is essential for reproductive function.3,4) Therefore, progesterone can be utilized as a marker for the diagnosis of early pregnancy. Antibodies that bind specifically to progesterone are essential in developing immunoassay methods to measure the progesterone level.Fluorescence polarization immunoassay (FPIA) is based on the principles of two technologies: competitive antibody binding and fluorescence polarization. The competitive antibody-binding assay is based on the competition between free progesterone and fluorescence-labeled progesterone tracer for the binding site on the antibody. The fluorescence polarization assay is based on the principle that molecules rotate in liquid and the rate of rotation is related to the size of the molecule. The disturbance of polarized fluorescence is higher in a small fluorescence-labeled antigen (tracer) than in antibody-bound tracer. When a small fluorescence molecule is excited with polarized light, its rapid Brownian rotation leads to randomization of the molecular orientation before fluorescence emission occurs, and the polarization becomes low. If the molecule binds to a large specific antibody (MW 150000 Da), rotation slows and the emitted fluorescence retains substantial polarization. Hence the degree of antibody binding may be monitored by measurement of fluorescence polarization without physical separation steps.Because of the dependence on molecular size in FPIA, it is particularly suited to the assay of small haptens such as steroids and drugs. Its major applications are in clinical diagnostics, especially in the areas of therapeutic drug monitoring and drug-abuse screening.5,6) A fully automated instrument, the Abbott TDx analyzer, incorporating a polarization fluorometer and a versatile diluter-dispenser has been introduced. For progesterone-related investigations, several hybridoma cell lines producing monoclonal antibodies against immunogens of conjugation-site specific progesterone have been established, as previously described. 7,8) Several immunoassays were reported such as enzyme immunoassay (EIA), 7) cytometric fluoroimmunoassay (CFIA), 9) visual membrane EIA, 8) and FPIA to measure progesterone levels. 10)In this investigation, an immunocomplex single reagent (SR) is developed to simplify the FPIA procedure (one-step FPIA) and its performance characteristics were evaluated in determining progesterone levels. MATERIALS AND METHODS Instruments and ChemicalsProgesterone, progesterone-3-(O-carboxymethyl)oxime (P-3CMO), 11a-hemisuccinyloxyprogesterone (P-11HS), N-hydroxysuccinimide (NHS), dimethylformamide (DMF), 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-hydroch...

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The inability of some synthetic progestagens to maintain pregnancy in the mare

Cited by 43 publications

References 9 publications

Endocrine and ultrasonographic characterization of a successful pregnancy in a Sumatran rhinoceros (Dicerorhinus sumatrensis) supplemented with a synthetic progestin

Endocrine and ultrasonographic characterization of a successful pregnancy in a Sumatran rhinoceros (Dicerorhinus sumatrensis) supplemented with a synthetic progestin

Pregnancy loss during the embryonic period

Development of One-Step Fluorescence Polarization Immunoassay for Progesterone.

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