Glycine transport in mouse eggs ad preimplantation conceptuses
| Autor: | Allan L. Campione, James M. Gorman, Lon J. Van Winkle, N. Haghighat |
|---|---|
| Rok vydání: | 1988 |
| Předmět: |
Sarcosine
Cytochalasin B ATPase Glycine Biophysics Lithium Biology Biochemistry Ouabain Choline Mice chemistry.chemical_compound Chlorides Leucine Cations medicine Animals Amino Acids reproductive and urinary physiology Ovum chemistry.chemical_classification Mice Inbred ICR Glycine transport urogenital system Sodium Biological Transport Cell Biology Membrane transport Amino acid Kinetics Blastocyst chemistry Mediated transport embryonic structures biology.protein Female Sodium-Potassium-Exchanging ATPase medicine.drug |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Biomembranes. 941:241-256 |
| ISSN: | 0005-2736 |
| DOI: | 10.1016/0005-2736(88)90185-x |
| Popis: | At least two Na + -dependent systems for glycine transport became detectable, while another became undetectable during preimplantation development of mouse conceptuses. Glycine was taken up by a process in eggs and cleavage-stage conceptuses which closely resembles system Gly. Mediated transport at these stages was more rapid at higher Cl − concentrations sigmoidally related to the exogenous Na + concentration, and strongly inhibited by sarcosine but not by amino acids with larger side chains. Moreover, neither Li + nor choline could substitute for Na + in stimulating glycine transport. System Gly was the only mediated process detected for glycine uptake in unfertilized and fertilized eggs and two-cell conceptuses, but two, less conspicuous, sarcosine-resistant, Na + -dependent components of transport also appeared to be present in eight-cell conceptuses. One of the latter components seemed to remain relatively inconspicuous when conceptuses formed blastocysts, while system Gly became undetectable. In contrast, the other less conspicuous component in eight-cell conceptuses appeared to become the most conspicuous transport process in blastocysts. The latter process, previously designated system B 0,+ , was shown here also to interact strongly with a broad scope of zwitterionic and cationic amino acid structures. Moreover, transport of glycine via system B 0,+ , was more rapid at higher Cl − concentrations, and this Na + -dependent process as well as Na + -independent leucine uptake were inhibited by choline. Furthermore, Na + -dependent amino acid transport in two-cell conceptuses and blastocysts was inhibited by 1.0 or 10 mM ouabain, but the inhibition was incomplete at both concentrations. Since Na + /K + -ATPase has not been detected in two-cell conceptuses, inhibition of amino acid transport by ouabain may not have bee due solely to an effect on this enzyme. The level of system Gly activity decreased during the development of eight-cell conceptuses from eggs, and this decrease could contribute to an associated decline in intracellular glycine. Since other amino acids begin to compete strongly with glycine for transport when system B 0,+ replaces system Gly in conceptuses, this qualitative change in transport activity may help account for a further decrease in the glycine content of conceptuses, reported elsewhere to occur after they form blastocysts. |
| Databáze: | OpenAIRE |
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