The overall objective of the proposed research is to develop two methods of testing the viability of preimplantation mammalian embryos. The first is to measure the rate of uptake of metabolic substrates, either glucose or pyruvate, by single preimplantation embryos incubated in a microdroplet of medium. The substrates will be estimated by a very sensitive ultramicrochemical method which allows measurements in the picogram per hour range. The possibility of developing a functional test based on stimulating the uptake of glucose by exogeneous hormones or sera will also be examined. The second approach is to monitor the intracellular pH of individual cells of preimplantation embryos. The pH will be monitored by means of pH sensitive fluorogenic dyes detected by microfluorometry. A functional test will be based on whether the cells can regulate their intracellular pH by exposing them to either alkaline or acid loads. If criteria for selective embryos for transfer can be formulated, their effectiveness will be tested by embryo transfer experiments. The mouse and the rabbit will be used as animal models.

Project Start
1986-04-01
Project End
1989-03-31
Budget Start
1988-04-01
Budget End
1989-03-31
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Harvard University
Department
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
Baltz, J M; Smith, S S; Biggers, J D et al. (1997) Intracellular ion concentrations and their maintenance by Na+/K(+)-ATPase in preimplantation mouse embryos. Zygote 5:1-9
Baltz, J M (1993) Intracellular pH regulation in the early embryo. Bioessays 15:523-30
Baltz, J M; Biggers, J D; Lechene, C (1993) A novel H+ permeability dominating intracellular pH in the early mouse embryo. Development 118:1353-61
Baltz, J M; Biggers, J D; Lechene, C (1991) Two-cell stage mouse embryos appear to lack mechanisms for alleviating intracellular acid loads. J Biol Chem 266:6052-7
Baltz, J M; Biggers, J D; Lechene, C (1990) Apparent absence of Na+/H+ antiport activity in the two-cell mouse embryo. Dev Biol 138:421-9
Gardner, D K; Clarke, R N; Lechene, C P et al. (1989) Development of a noninvasive ultramicrofluorometric method for measuring net uptake of glutamine by single preimplantation mouse embryos. Gamete Res 24:427-38
Baltz, J M; Cardullo, R A (1989) On the number and rate of formation of sperm-zona bonds in the mouse. Gamete Res 24:1-8
Butler, J E; Lechene, C; Biggers, J D (1988) Noninvasive measurement of glucose uptake by two populations of murine embryos. Biol Reprod 39:779-86