Oestrogen production by blastocyst and early embryonic tissue of various species
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High aromatase activity in preimplantation trophoblast of pigs was associated with the maternal recognition of pregnancy and the occurrence of superficial implantation in this species.Abstract:
Summary. Oestrogen synthesis by the early embryo in vitro was studied with tissue from pigs, sheep, cows, roe deer, ferrets, cats, rabbits and a plains viscacha. Definitive evidence for aromatase activity and oestrogen synthesis in preimplantation trophoblast was obtained for the pig with the formation of oestrone, oestradiol-17\g=b\ and oestradiol-17\g=a\from 3H-labelled androstenedione and dehydroepiandrosterone. Aromatase activity was appreciably lower in all other species studied, and labelled oestrogens were recovered only from incubations of allantochorionic tissue of roe deer, recovered shortly after implantation, and from pooled samples of early embryonic tissue of cows. High aromatase activity in preimplantation trophoblast of pigs was associated with the maternal recognition of pregnancy and the occurrence of superficial implantation in this species.read more
Citations
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Establishment of pregnancy in the pig: I. Interrelationships between preimplantation development of the pig blastocyst and uterine endometrial secretions.
TL;DR: Electrophoresis of protein in pregnant uterine flushings indicated that the appearance of three basic uterine proteins were associated with the increase in estrogen, and increases in PGF and PGE2 were associated closely with estrogen production and blastocyst elongation.
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The functions of uterine secretions
R. M. Roberts,Fuller W. Bazer +1 more
TL;DR: The likely functions of uterine secretions, often termed histotroph, in the nurture of the early conceptus are reviewed and evidence has accumulated to suggest that uteroferrin, rather than functioning as an acid phosphatase, is involved in transporting iron to the conceptus.
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Establishment of pregnancy in the pig: II. Cellular remodeling of the porcine blastocyst during elongation on day 12 of pregnancy.
TL;DR: The morphology of pig blastocysts changes dramatically just preceding initial attachment of the trophoblast to the uterine epitheliuin, and possible mechanism(s) involved with changes in blastocyst morphology are investigated.
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Role of conceptus secretory products in establishment of pregnancy
TL;DR: Conceptuses produce steroids, prostaglandins, proteins and possibly other unidentified agents which may play a role in the establishment and maintenance of pregnancy, and inhibiting uterine production of luteolytic amounts of PGF-2 alpha allows for maintenance of CL function.
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Embryonicsteroids and the establishment of pregnancy in pigs
TL;DR: Evidence is provided for an involvement of oestrogen in the maternal recognition of pregnancy in the sow and the roles of these factors in control of vascular permeability, blood flow, placental attachment and immunological protection certainly indicate that, in addition to oestrogens, other factors are involved in the establishment of pregnancy.
References
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Theory of maternal recognition of pregnancy in swine based on estrogen controlled endocrine versus exocrine secretion of prostaglandin F2alpha by the uterine endometrium.
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Studies on the development of mouse embryos in vitro. IV. Interaction of energy sources.
TL;DR: In this article, the interactions of a number of possible energy sources for in-vitro development of 2-cell mouse ova were examined using statistical experimental designs, which indicated that glucose has no beneficial effect on development when employed with the optimum concentration of pyruvate.
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Steroid Hormone Production by Pig Blastocysts
TL;DR: In the sheep and pig, the recognition signal has been transmitted even before the embryonic tissue becomes intimately attached to the uterine epithelium and is therefore clearly distinct from implantation.
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Growth, protein content and distribution of early pig embryos.
TL;DR: Development of porcine conceptuses included transitions of five stages: blastocysts of spherical, ovoid, and tubular forms containing an embryonic disc and trophoblast, extremely elongated filamentous blastocyst, and stages of embryogenesis between days 9 and 18 after mating.