Characterization of Bovine Conceptus Proteins Produced during the Peri- and Postattachment Periods of Early Pregnancy1

Godkin, James D.; Lifsey, Ben J.; Gillespie, B. E.

doi:10.1095/biolreprod38.3.703

Cited by 48 publications

(24 citation statements)

References 24 publications

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“…However, IFNT is likely to no longer be a major factor in maintaining the CL during the second month of pregnancy since IFNT secretion from the developing conceptus peaks by day 23 of pregnancy and then dramatically decreases during the next few weeks (Godkin et al, 1988;Stojkovic et al, 1995). This provokes the obvious question: What maintains the CL after day 30 of pregnancy when IFNT is no longer present?…”

Section: Period III Prevention Of Later Luteolysis During Pregnancy mentioning

confidence: 99%

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Wiltbank¹,

Meidan²,

Ochoa³

et al. 2016

Anim Reprod

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In ruminants, there are specific times during the estrous cycle or pregnancy when the corpus luteum (CL) may undergo regression. This review has attempted to summarize the physiological and cellular mechanisms involved in CL regression or maintenance during four distinct periods. The first period is near day 7 when animals that are ovulating after a period of low circulating progesterone (P4), such as first pubertal ovulation or first postpartum ovulation, are at risk of having a premature increase in Prostaglandin F2α (PGF) secreted from the uterus resulting in early CL regression and a short estrous cycle. The second period is when normal luteolysis occurs at day 18-25 of the cycle or when the CL is rescued by interferon-tau secreted by the elongating embryo. The uterine mechanisms that determine the timing of this luteolysis or the prevention of luteolysis have been generally defined. Induction and activation of endometrial E2 receptors result in induction of endometrial oxytocin receptors that can now be activated by normal pulses of oxytocin. Of particular importance is the observation that the primary mechanisms are only activated through local (ipsilateral) and not a systemic route due to transfer of PGF from the uterine vein to the ovarian artery. In addition at the CL level, studies are providing definition to the cellular and molecular mechanisms that are activated in response to uterine PGF pulses or pregnancy. The third period that is discussed occurs in the second month of pregnancy (day 28-60) when undefined mechanisms result in CL maintenance of an ipsilateral CL but regression of a contralateral (opposite side from pregnancy) CL. The final period that is discussed is regression of the CL just prior to parturition. Although, cortisol from the fetus appears to be the primary initiator of luteolysis, PGF seems to be the final signal that causes regression of the CL. Thus, in all four periods, regression of the CL is likely to be caused by the direct actions of PGF that is secreted from the uterus. The uterine mechanisms that result in secretion of PGF seem to be normally inhibited during the early luteal phase, making short luteal phases not a normal event, and are altered during early pregnancy (day 18-25) resulting in prevention of luteolysis. During much of pregnancy, the mechanisms that cause PGF secretion from the uterus in response to oxytocin are intact but luteolysis does not normally occur, perhaps due to lack of efficient utero-ovarian transfer of PGF.

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Section: Period III Prevention Of Later Luteolysis During Pregnancy mentioning

confidence: 99%

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Wiltbank¹,

Meidan²,

Ochoa³

et al. 2016

Anim Reprod

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“…Each piece (5-6 × 3 mm cutting) of day 22 conceptuses was transferred separately to sterile Petri dishes containing 2 ml modified MEM. Culture conditions were as described previously [6]. Conceptuses were incubated at 37 C on a rocking platform in a gaseous atmosphere of 50% O 2 , 45% N 2 , and 5% CO 2 (by volume).…”

Section: In Vitro Culture Of Conceptusesmentioning

confidence: 99%

“…eletrophoretically characterized [6]. Bovine maternal recognition of pregnancy is mediated by conceptus secretory protein, known as bovine trophoblast protein-1 (bTP-1).…”

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confidence: 99%

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Secretion and Immunolocalization of Retinol-Binding Protein in Bovine Conceptuses during Periattachment Periods of Early Pregnancy.

Liu

2002

Journal of Reproduction and Development

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Abstract. The purpose of the study was to determine and compare the secretion of RBP by bovine spherical, elongating and filamentous conceptuses, and to identify the cellular location of RBP in developing conceptuses by immmunocytochemistry. Bovine conceptuses were removed from the uterus between days 13 and 22 of pregnancy. Events of early bovine embryonic development were observed. The conceptuses underwent a transformation from a spherical to a filamentous morphology during the periattachment period of placentation. Isolated conceptuses were cultured in a modified minimum essential medium in the presence of radiolabeled amino acids. Presence of retinol-binding protein (RBP) in culture medium was determined by immunoprecipitation using bovine placental anti-RBP serum. Presence of immunoreactive RBP in detectable quantities in spherical blastocyst (day 13) culture medium was evident. Increased amounts of RBP were clearly detected in cultures on days 14 and 15, the time of elongating conceptuses. RBP was abundant in cultures on day 22, when the conceptuses were filamentous. Cellular sources of RBP in day 15 and 22 conceptuses were determined by immunocytochemistry with anti-RBP serum. Strong immunoreactive RBP was localized in trophectoderm of day 15 conceptuses, and in epithelial cells lining the chorion and allantois of day 22 conceptuses. RBP originating from the conceptus may serve to transport retinol locally from the uterus to embryonic tissues. Secretion of RBP by spherical blastocysts (day 13) suggests that retinol is needed for initiating the early events of embryonic development. Increased secretion of RBP on days 14 and 15, the time of elongating conceptuses, was coincident with the timing of rapid trophoblast hyperplasia and remodeling. Greater secretion of RBP by the filamentous conceptus (day 22) coincided with the timing of differentiation of the chorion and allantois as well as growth of the embryo proper. Production of RBP by the developing conceptuses may be indicative of an important role for conceptus RBP in the transport, availability and metabolism of retinol during early pregnancy.

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“…Caso contrário, na presença de um concepto viável, a secreção de proteínas trofoblásticas impede a liberação de PGF 2α pelo endométrio (Bazer et al 1986, Godkin et al 1988) e facilita a manutenção do CL (Knickerbocker et al 1986). Nos bovinos o IFN-τ (interferon tau) é uma glicoproteína secretada pelo trofoblasto, que atua como uma molécula anti-luteolítica.…”

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Produção de progesterona in vitro pelas células do corpo lúteo bovino ao longo da gestação

et al. 2007

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O presente trabalho foi desenvolvido para testar a hipótese de que células luteínicas bovinas em cultivo, provenientes dos três terços de gestação, comportam-se da mesma maneira que células in vivo em relação à produção de P4. Foram coletadas amostras de corpos lúteos (CL) de 90 (n=3), 150 (n=3) e 210 (n=3) dias de gestação obtidos em abatedouro. Sob condições assépticas, as células foram mecanicamente dispersas e cultivadas em placas de 96 poços. Após 24 horas de cultivo foram feitas a lavagem dos poços e a adição do precursor pregnenolona. Os tratamentos foram realizados em octuplicata para cada tempo de tratamento (24, 48 e 96 horas) com três repetições de cada período gestacional. As amostras de meio de cultura e as células foram coletadas 24, 48 e 96 horas após adição do precursor e acondicionadas em freezer a -20ºC até o processamento. A progesterona foi dosada através de radioimunoensaio e o conteúdo protéico pelo método de Lowry. Os resultados foram analisados estatisticamente e considerados diferentes quando p<0.05. Foi observada maior produção de P4 aos 90 dias de gestação (35,277±0,075), posterior decréscimo aos 150 dias (28,820±0,231) e novo aumento aos 210 dias (32,777±0,099). A produção de P4 em células cultivadas por 24 horas foi maior (p<0,05) em células oriundas do grupo de 90 dias (2,912±0,047) quando comparado a 150 (2,669±0,137) e 210 dias (2,741±0,088). As 48 e 96 horas de cultivo, células luteínicas bovinas de 90 dias produziram mais P4 que células de 210 dias (2,934±0,029 e 2,976±0,121 respectivamente x 2,760±0,059 e 2,695±0,149, respectivamente; p<0,05), que por sua vez produziram mais do que células de 150 dias (2,334±0,084 para 48 horas e 2,205±0,136 para 96 horas). Aos 150 dias de gestação a produção de progesterona apresentou diminuição gradativa ao longo das 96 horas de cultivo. Essas diferenças podem ser explicadas pela expressão gênica diferencial de enzimas ou também de fatores presentes na cascata esteroidogênica de acordo com a idade gestacional. Este modelo de cultura celular luteínica poderá ser utilizado em estudos funcionais uma vez que o padrão de secreção de P4 mimetizou o que ocorre in vivo.

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Characterization of Bovine Conceptus Proteins Produced during the Peri- and Postattachment Periods of Early Pregnancy1

Cited by 48 publications

References 24 publications

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Maintenance or regression of the corpus luteum during multiple decisive periods of bovinepregnancy

Secretion and Immunolocalization of Retinol-Binding Protein in Bovine Conceptuses during Periattachment Periods of Early Pregnancy.

Produção de progesterona in vitro pelas células do corpo lúteo bovino ao longo da gestação

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