Mechanism of Ruminant Placental Lactogen Action: Molecular and in Vivo Studies

Gertler, Arieh; Djiane, Jean

doi:10.1006/mgme.2002.3303

Cited by 42 publications

(33 citation statements)

References 74 publications

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“…Surprisingly, bovine STC1 and GRP mRNA levels were higher in endometrium from day 18 cyclic than day 18 pregnant cows , suggesting species-specific control of expression of these genes. A homodimer of the PRL receptor (PRLR), as well as a heterodimer of PRLR and GH receptor, transduce signals by ovine CSH1/placental lactogen (Gertler & Djiane 2002). In the ovine uterus, PRLR gene expression is unique to GE (Cassy et al 1999, Stewart et al 2000.…”

Section: Csh1 Regulation Of Uterine Gland Morphogenesis and Secretorymentioning

confidence: 99%

Genes involved in conceptus–endometrial interactions in ruminants: insights from reductionism and thoughts on holistic approaches

Spencer¹,

Sandra²,

Wolf³

2008

Reproduction

274

253

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This review summarizes new knowledge on expression of genes and provides insights into approaches for study of conceptus-endometrial interactions in ruminants with emphasis on the peri-implantation stage of pregnancy. Conceptus-endometrial interactions in ruminants are complex and involve carefully orchestrated temporal and spatial alterations in gene expression regulated by hormones from the ovary and conceptus. Progesterone is the hormone of pregnancy and acts on the uterus to stimulate blastocyst survival, growth, and development. Inadequate progesterone levels or a delayed rise in progesterone is associated with pregnancy loss. The mononuclear trophectoderm cells of the elongating blastocyst synthesize and secrete interferon-t (IFNT), the pregnancy recognition signal. Trophoblast giant binucleate cells begin to differentiate and produce hormones including chorionic somatomammotropin 1 (CSH1 or placental lactogen). A number of genes, induced or stimulated by progesterone, IFNT, and/or CSH1 in a cell-specific manner, are implicated in trophectoderm adhesion to the endometrial luminal epithelium and regulation of conceptus growth and differentiation. Transcriptional profiling experiments are beginning to unravel the complex dynamics of conceptus-endometrial interactions in cattle and sheep. Future experiments should incorporate physiological models of pregnancy loss and be complemented by metabolomic studies of uterine lumen contents to more completely define factors required for blastocyst survival, growth, and implantation. Both reduction and holistic approaches will be important to understand the multifactorial phenomenon of recurrent pregnancy loss and provide a basis for new strategies to improve pregnancy outcome and reproductive efficiency in cattle and other domestic animals.

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Section: Csh1 Regulation Of Uterine Gland Morphogenesis and Secretorymentioning

confidence: 99%

Genes involved in conceptus–endometrial interactions in ruminants: insights from reductionism and thoughts on holistic approaches

Spencer¹,

Sandra²,

Wolf³

2008

Reproduction

274

253

View full text Add to dashboard Cite

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“…Ruminant PL may also bind heterodimers of homologous PRLR and GHR. 3 The structural basis for the cross-reactivity observed between primate GH and PRLR but not between PRL and GHR is of fundamental importance for a full understanding of PRL biology. Binding of GH to GHR, of primate GH to PRLR and of PRL to PRLR has been studied thoroughly by site-directed mutagenesis, and residues contributing to the binding energy have been identified.…”

Section: Introductionmentioning

confidence: 99%

Solution Structure of Human Prolactin

Teilum

Hoch

Goffin

et al. 2005

Journal of Molecular Biology

114

110

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We report the solution structure of human prolactin determined by NMR spectroscopy. Our result is a significant improvement over a previous structure in terms of number and distribution of distance restraints, regularity of secondary structure, and potential energy. More significantly, the structure is sufficiently different that it leads to different conclusions regarding the mechanism of receptor activation and initiation of signal transduction. Here, we compare the structure of unbound prolactin to structures of both the homologue ovine placental lactogen and growth hormone. The structures of unbound and receptor bound prolactin/ placental lactogen are similar and no noteworthy structural changes occur upon receptor binding. The observation of enhanced binding at the second receptor site when the first site is occupied has been widely interpreted to indicate conformational change induced by binding the first receptor. However, our results indicate that this enhanced binding at the second site could be due to receptor-receptor interactions or some other free energy sources rather than conformational change in the hormone. Titration of human prolactin with the extracellular domain of the human prolactin receptor was followed by NMR, gel filtration and electrophoresis. Both binary and ternary hormone-receptor complexes are clearly detectable by gel filtration and electrophoresis. The binary complex is not observable by NMR, possibly due to a dynamic equilibrium in intermediate exchange within the complex. The ternary complex of one hormone molecule bound to two receptor molecules is on the contrary readily detectable by NMR. This is in stark contrast to the widely held view that the ternary prolactinreceptor complex is only transiently formed. Thus, our results lead to improved understanding of the prolactin-prolactin receptor interaction.

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“…Although its function and secretory control are not completely understood, in vivo and in vitro studies have suggested PL to have multiple somatogenic (GH-like) and lactogenic (PRLlike) biological effects, depending on the species, such as placental angiogenesis, maternal and foetal intermediate metabolism, mammary gland development and function, ovarian and placental steroidogenesis, growth rate and luteal function (Patel et al 1996, Pedersen et al 1998, Gregoraszczuk et al 2000, Corbacho et al 2002, Gertler & Djiane 2002, Gootwine 2004. Bovine (b) PL is more structurally similar to PRL than GH and is secreted into both the maternal and foetal systems (Gootwine 2004), with a decrease in foetal concentrations during the course of gestation and a peak in maternal plasma during the last trimester of pregnancy (Byatt et al 1992a).…”

Section: Introductionmentioning

confidence: 99%

Expression profile and protein levels of placental products as indirect measures of placental function in in vitro-derived bovine pregnancies

Bertolini¹,

Wallace²,

Anderson³

2006

Reproduction

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Bovine conceptus development and its association with placental proteins present in maternal, foetal and neonatal plasma and foetal (amniotic and allantoic) fluids were investigated in in vivo-and in vitro-produced (IVP) concepti and newborn calves. Females were superovulated to obtain control embryos, whereas IVP embryos were derived from established in vitro procedures. Pregnant animals were slaughtered on days 90 or 180 of gestation or allowed to develop to term for the assessment of physical traits. Foetal, maternal and neonatal blood and foetal fluids were collected for the determination of bovine placental lactogen (bPL) and bovine pregnancy-specific protein B (bPSPB) concentrations. Placental transcripts for bPL and bPSPB, determined by quantitative RT-PCR, were elevated in IVP placentomes. No major physical differences were observed between groups on day 90, but concentrations of bPL and bPSPB were higher in foetal plasma and allantoic fluid of IVP concepti in day 180 pregnancies, which were correlated with larger uterine and conceptus traits. Maternal concentrations of bPL in IVP pregnancies were lower than controls during the last 8 weeks of gestation, to become similar as parturition approached. Newborn IVP calves and foetal membranes were larger and displayed higher concentrations of plasma bPL than controls (10 and 60 min after birth). Our results indicated that differential patterns of secretion of bPL and bPSPB into the maternal and foetal systems occurred at distinct stages of gestation, and these were associated with altered conceptus development after in vitro embryo manipulations, indirectly demonstrating deviations in placental function in IVP pregnancies. Reproduction (2006) 131 163-173 IntroductionWith the onset of the trophoblast apposition to the endometrium during the process of bovine placenta formation and development, large granulated cells, the trophoblast binucleate cells (BCs), migrate from the trophectoderm to fuse with uterine epithelial cells (Wooding 1992), forming short-lived trinucleate cells. This phenomenon occurs throughout pregnancy in cattle, but the number and period of existence of trinucleate cells decline towards the end of gestation (Wooding 1992, Green et al. 2000. Binucleate cells comprise about 20% of the trophoblast cells and are responsible for hormones and bioactive products important for the regulation of foetal growth and development (Anthony et al. 1995, Green et al. 2000, Schlafer et al. 2000. The contents of the membranebounded secretory granules of BCs are released by exocytosis towards the maternal capillary bed, reaching the maternal blood system (Wooding 1992). Many proteins are produced by the BCs, including placental lactogen (PL) and a range of glycoproteins (Wooding 1992), such as pregnancy-specific protein B (PSPB) (Butler et al. 1982).PL lactogen is a member of the growth hormone (GH)/prolactin (PRL) gene family synthesized and stored in secretory granules of the trophoblast BCs (Byatt et al. 1992a, Wooding 1992, Gootwine 2004. Although ...

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Mechanism of Ruminant Placental Lactogen Action: Molecular and in Vivo Studies

Cited by 42 publications

References 74 publications

Genes involved in conceptus–endometrial interactions in ruminants: insights from reductionism and thoughts on holistic approaches

Genes involved in conceptus–endometrial interactions in ruminants: insights from reductionism and thoughts on holistic approaches

Solution Structure of Human Prolactin

Expression profile and protein levels of placental products as indirect measures of placental function in in vitro-derived bovine pregnancies

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