Abstract
The pulse-chase technique was used to study the uptake and turnover of glucose carbon by mouse embryos in vitro. During a 1 h pulse the uptake of glucose into all embryonic fractions increased between the eight-celled and the morula-early blastocyst stages of development. Whilst most of the glucose carbon entered the non-glycogen, acid-soluble pool, significant amounts were isolated in acid-insoluble macromolecules and, at the later stage of development, in acid-soluble glycogen.