Changes of the adenine ribonucleotide content during preimplantation development of mouse embryos in vivo and in vitro

Abstract

The amount of ATP, ADP and AMP and also the adenylate energy charge and the ATP/ADP ratio were determined in preimplantation mouse embryos (strain NMRI) in vivo. The ATP content decreased from 0.64 pmol at fertilization to 0.21 pmol in late blastocysts. ADP decreased from 0.1 pmol in the zygote to 0.06 pmol in 4-8 cell embryos and increased again to 0.15 pmol in late blastocysts. AMP changed considerably at the 1-cell and the 2- cell stage and increased from 0.04 to 0.2 pmol between the 4-cell and the late blastocyst stage. These developmental changes between fertilization and implantation result in a continuous decline of the total amount of adenine ribonucleotides (from 0.79 to 0.64 pmol), of the adenylate energy charge (from 0.87 to 0.45) and of the ATP/ADP ratio (from 64. to 1.4). In C57BL embryos developing to the 2-cell stage in vivo or in vitro there was a decrease in ATP content, as in NMRI embryos in vivo whereas the ATP content remained unchanged in MNRI embryos during culture to the 2-cell stage (no further development in vitro). In blastocysts cultured for 24 h in media supporting differentiation during implantation (MEM and NCTC-109) the content of ATP and ADP increased but AMP remained constant. The total adenine ribonucleotide content rose to 1 pmol and the ATP/ADP ratio and adenylate energy charge remained unchanged. After 48 h of culture in the two media to late blastocysts there was a decrease in ATP, an increase in AMP and a decline in adenylate energy charge and ATP/ADP ratio, as occurs in vivo.