Uptake of a mixture of amino acids by mouse blastocysts.
Preimplantation mouse embryos exhibit growth at the blastocyst stage when there is a dramatic increase in protein content between days 4 and 5 after hCG treatment. This increse in protein synthesis requires the uptake of amino acids from the surrounding medium, but the consumption of individual amino acids present as a mixture has not been examined. We therefore measured the simultaneous depletion of 18 amino acids by mouse blastocysts in culture on days 4 and 5 after hCG treatment. Two culture media were used: one with amino acids present at concentrations largely based on those reported to give optimal rates of embryo development (M16/mix AA), and a second with the amino acids each at 0.1 mmol l-1 (M16/0.1 AA). After derivatization with o-phthaldialdehyde to yield highly fluorescent products, amino acid concentrations in the media were measured by HPLC. On day 4, seven amino acids were depleted from M16/mix AA at rates significantly greater than zero: aspartate, arginine, glycine, alanine, isoleucine, leucine and lysine; on day 5, nine amino acids were depleted at significant rates: aspartate, glutamate, asparagine, tyrosine, methionine, valine, phenylalanine, isoleucine and leucine. Average amino acid depletion from M16/mix AA was 32% greater on day 5 than on day 4. Aspartate, glutamate, arginine, isoleucine and leucine appeared to be the key amino acids sought by embryos on both days tested. Embryos grown in amino-acid-containing media appeared morphologically normal and their volume increased compared with embryos cultured in the absence of amino acids.
Lamb
V K
VK
Department of Biology, University of York, Heslington, UK.
Leese
H J
HJ
D000596:Amino Acids / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA
D000596:Amino Acids; D003470:Culture Media