The mammalian fetal membranes

Perry, J. S.

doi:10.1530/jrf.0.0620321

Cited by 135 publications

(95 citation statements)

References 7 publications

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“…These data confirm those of Geisert et al (1982a), who reached the same conclusion concerning pig embryos up to about 10 mm in diameter on the basis of mitotic index and DNA content. On the basis of the rapidity with which pig blastocysts exhibit struchual change and elongate, Perry (1981) suggested that elongation is …”

Section: Discussionmentioning

confidence: 99%

Changes in morphology, cell number, cell size and cellular estrogen content of individual littermate pig conceptuses on days 9 to 13 of gestation.

Pusateri

Rothschild²,

Warner³

et al. 1990

Journal of Animal Science

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Days 9 to 12 of gestation in the pig are marked by a pronounced asynchrony among littermate embryos. Previously published studies have suggested that the most advanced embryos within a litter by d 12 synthesize greater amounts of estrogen. Embryonic estrogen secretion has been shown to advance endometrial secretions, which may adversely affect less-developed littermates. To date, however, no comprehensive study of the developmental pattern and synthetic activities of individual littermate embryos during this period has been conducted. Litters were collected from Yorkshire gilts on d 9 (n = 11), 11 (n = 10), 12 (n = 5) and 13 (n = 8). Size (greatest diameter), DNA content (cell number), protein:DNA ratio and estrone (E1) and estradiol-17 beta (E2) content were determined for each embryo. Embryo sizes (mm greatest diameter) were (x +/-SEM) 1 +/-.1, 5.6 +/-.7, 41.2 +/-11.7 and 405.7 +/-16.7 on d 9, 11, 12 and 13, respectively. The daily variation in embryo size, expressed as CV was 82% on d 9, 145% on d 11, 206% on d 12 and 46% on d 13. DNA per embryo increased progressively from d 9 to 13, whereas the protein:DNA ratio declined. Content of E1 and E2 per embryonic cell was greatest on d 11 and d 12 before declining markedly on d 13. Cell number and embryo size were correlated positively in embryos 1 to 7 mm (P less than .01) and embryos greater than 100 mm (P less than .01) but not in embryos 8 to 100 mm. period has been conducted. Litters were collected from Yorkshire gilts on d 9 (n = 1 l), 11 (n = lo), 12 (n = 5 ) and 13 (n = 8). Size (greatest diameter), DNA content (cell number), protein:DNA ratio and estrone (El) and estradiol-17P (EL) content were determined for each embryo. Embryo sizes (mm greatest diameter) were (jr f SEM) 1 f .l, 5.6 f .7,41.2 f 11.7 and 405.7 f 16.7 on d 9, 11, 12 and 13, respectively. The daily variation in embryo size, expressed as CV was 82% on d 9, 145% on d 11, 206% on d 12 and 46% on d 13. DNA per embryo increased progressively from d 9 to 13, whereas the proteimDNA ratio declined. Content of El and E2 per embryonic cell was greatest on d 11 and d 12 before declining markedly on d 13. Cell number and embryo size were correlated positively in embryos 1 to 7 mm (P < .01) and embryos >lo0 mm (P < .01) but not in embryos 8 to 100 m. Initial rapid elongation appears to result both from a redistribution of embryonic cells and an increase in cell number. These data suggest that embryonic diversity and differential estrogen synthesis among littermate embryos is marked on d 11 and d 12.

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Section: Discussionmentioning

confidence: 99%

Changes in morphology, cell number, cell size and cellular estrogen content of individual littermate pig conceptuses on days 9 to 13 of gestation.

Pusateri

Rothschild²,

Warner³

et al. 1990

Journal of Animal Science

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“…In the mouse this invasion is accompanied by the complete death and delamination of the uterine epithelium (Enders et al 1980) whereas in the human, the trophectoderm intrudes through the uterine epithelium and the blastocyst passes through the endometrium (Aplin 1991). In species with invasive haemochorial placentation the uterus responds to an implanting blastocyst by undergoing extensive modifications that result in the transformation of the endometrium into the decidua, while in ungulates such as the sheep in which little invasion occurs, attachment of the trophoblast to the endometrium results in a superficial form of implantation with the formation of a synepitheliochorial placenta (Perry 1981).…”

Section: A Comparative View Of Early Pregnancy In Different Mammalianmentioning

confidence: 99%

Review: The role of leukaemia inhibitory factor in the establishment of pregnancy

Vogiagis

Salamonsen²

1999

Journal of Endocrinology

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Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine required for blastocyst implantation in mice. Uterine expression of LIF and that of its receptors has been demonstrated in a number of mammalian species indicating that LIF may have widespread importance in the establishment of pregnancy. The variations in the reaction of the uterus in preparation for and during implantation are considerable between species and understanding the differences and similarities assists in the interpretation of how this cytokine functions. Recent studies suggest that reduced endometrial LIF contributes to human infertility. Studies also demonstrate a potential role in placentation and fetal development. Thus, LIF has become an important cytokine warranting further investigation in the human. It is anticipated that when the mechanisms underlying normal embryonic and endometrial development are elucidated, fertility and infertility will be more precisely understood and hence able to be effectively controlled.

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“…The blastocysts are thus encapsulated beneath the uterine luminal surface [21]. In contrast, the bovine blastocyst never becomes embedded in the uterine wall in the same manner as those of primates and rodents.…”

Section: Discussionmentioning

confidence: 99%

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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The mammalian fetal membranes

Cited by 135 publications

References 7 publications

Changes in morphology, cell number, cell size and cellular estrogen content of individual littermate pig conceptuses on days 9 to 13 of gestation.

Changes in morphology, cell number, cell size and cellular estrogen content of individual littermate pig conceptuses on days 9 to 13 of gestation.

Review: The role of leukaemia inhibitory factor in the establishment of pregnancy

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

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