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W R Edirisinghe

Publications and source records attributed to W R Edirisinghe.

40 records · Page 3Linked to original sources
PubMed1984

Studies of the distribution of glycogen between the inner cell mass and trophoblast cells of mouse embryos.

Autoradiographic and histochemical techniques were used to determine the localization of glycogen synthesized during in-vitro culture of preimplantation mouse embryos. During early cleavage embryos accumulated little glycogen and that which was synthesized was spread evenly in the blastomere cytoplasm. However, morula and early blastocyst stages accumulated relatively large amounts of glycogen, especially in the peripheral or trophoblastic cells in comparison to the inner cells or inner-cell-mass cells. Immunosurgical techniques were used to study the incorporation of radiolabelled glucose into the biochemical pools of inner-cell-mass and trophoblastic cells during culture for 24 h. In general, trophoblastic cells incorporated considerably more isotope than did inner-cell-mass cells, especially into the acid-soluble glycogen fraction. However, inner cell masses isolated on Day 4 of pregnancy incorporated more glucose into acid-soluble glycogen than did inner cells isolated from blastocysts at the end of culture for 24 h in isotope.

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PubMed1984

Degradation of biochemical pools labelled with [14C]glucose during culture of 8-cell and morula--early blastocyst-stage mouse embryos in vitro and in vivo.

When 8-cell mouse embryos were chase cultured for 24 h in vitro or in vivo (in uteri of pseudopregnant mice) there was no indication of utilization of the small amount of acid-soluble glycogen synthesized during the pulse. At the morula-early blastocyst stage of development almost 50% of the label incorporated during the pulse was found in the acid-soluble glycogen fraction. The biochemical pools at this stage were relatively stable in vitro and in vivo during a short (5 h) chase period. However, marked degradation of the acid-soluble glycogen pool occurred during long periods of exposure to the uterine environment and, over 48 h in utero, almost all of the label was lost from this pool. By contrast, embryos cultured in vitro for the same period retained greater than 60% of their acid-soluble glycogen. Utilization of glucose carbon in the acid-insoluble glycogen fraction occurred during in-vitro and in-vivo chase but there was a suggestion that the change in vivo was less than that in vitro. The non-glycogen macromolecular pool was relatively stable except during extended chase culture of morulae-early blastocysts when some utilization occurred. Under these conditions utilization was less in utero than in vitro. The experiments show that the uterine environment has a marked influence on the metabolism, particularly of glycogen, of the embryo and indicate that some factor in the uterus causes net degradation of acid-soluble glycogen by the embryo at the late preimplantation stage of development.

Animals↗
PubMed1984

Effect of parenteral administration of oestrogen and progesterone on the glycogen metabolism of mouse morulae--early blastocysts in vivo.

Morulae--early blastocysts were pulse-labelled with radioactive glucose and subsequently transferred for 24 h to ovariectomized recipients maintained on different hormone regimens. Embryos transferred to recipients treated with progesterone utilized more glycogen than did those incubated in untreated controls. Treatment with oestrogen alone had no significant effect on glycogen turnover of transferred embryos and, when given in combination with progesterone, antagonized the effect of progesterone. Priming doses of oestrogen given greater than 4 days before progesterone had no significant effect on the response to progesterone. The results indicate that the high levels of progesterone circulating in the mother before implantation cause glycogen degradation in the embryo and account for the low glycogen content of uterine embryos compared to those cultured in vitro in the presence of glucose.

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