Glycine uptake in pre-implantation mouse embryos: Kinetics and the effects of external [na+]

Hobbs J.G. and Kaye P.L. (1990) Glycine uptake in pre-implantation mouse embryos: Kinetics and the effects of external [na+]. Reproduction, Fertility and Development, 2 6: 651-660. doi:10.1071/RD9900651


Author Hobbs J.G.
Kaye P.L.
Title Glycine uptake in pre-implantation mouse embryos: Kinetics and the effects of external [na+]
Journal name Reproduction, Fertility and Development   Check publisher's open access policy
ISSN 1448-5990
Publication date 1990-01-01
Sub-type Article (original research)
DOI 10.1071/RD9900651
Volume 2
Issue 6
Start page 651
End page 660
Total pages 10
Subject 1103 Clinical Sciences
1309 Developmental Biology
1311 Genetics
1305 Biotechnology
1312 Molecular Biology
1310 Endocrinology
2743 Reproductive Medicine
Abstract The kinetic parameters (with standard errors) describing glycine uptake by mouse 2-cell embryos and blastocysts were determined by non-linear regression. Uptake at both stages was best described by a combination of a non-saturable component and a single saturable uptake system. During development, the rate constants for both components increased, as would be expected from the known increases in surface area, from 9-4 ± 3-7 pL per 10 min per embryo and 128 ± 12 fmol per 10 min per embryo in 2-cell embryos to 38.9 ± 2.1 pL per 10 min per embryo and 258 ± 15 fmol per 10 min per embryo in blastocysts. In contrast to earlier reports, there was no change in Km, which was 88 ± 13 Km in 2-cell embryos and 115 ± 10 iim in blastocysts. Reducing the external [Na+] from 230 mM increased Km for both stages. This effect on Km appeared to be related to [Na+]-2 or [Na+]-3. Kraax was increased in embryos of both stages by increasing [Na+] from 60 to 100 mM. However, whilst further increases to 400 mM were without major effect on uptake by 2-cell embryos, they inhibited uptake by blastocysts. This may result from osmotic effects on trophectodermal transport in the blastocysts. These results suggest that during development to blastocysts, the g/y-system that operates in 2-cell embryos may be modified to a less restricted system with a similar Km and a complex dependence on [Na+].
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import - Archived
 
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