Single Embryo Measurement of Basal-and Insulin-Stimulated Glucose Uptake

Working with single-mouse embryos at the blastocyst stage is difficult from a biochemical standpoint because of the paucity of tissue. Each blastocyst contains only 25 ng of total protein (1 ) and has a volume of approx 160 pL (2 ,3 ). In order to measure glucose uptake, many groups have pooled embryos to increase the signal of radioactive 2-deoxyglucose transported into the blastocyst. The advantage of this technique is that single-embryo uptake can be measured using not radioactivity but enzymatic cycling reactions that are based on the amplification of a fluorescent signal. This signal is a pyridine nucleotide.