The research proposed in this application is concerned with the intracellular pH (pHi) and metabolism of the oocyte and preimplantation stages of the mouse embryo. pH of the cells of single embryos will be measured by a method developed in our laboratories which uses one of the pH-sensitive fluorescent dyes. Detailed attention will be given to the absolute intracellular pH at different stages of development and its regulation. Specific attention will be paid to whether the pHi changes upon reinitiation of meiosis, fertilization, compaction, and/or exposure of the blastocyst to growth factors. The possibility of developing a non- invasive test of viability based on measurement of the acidification of the bathing medium when healthy embryos export protons to regulate their pHi will be investigated. The research is also concerned with the uptake of glutamine by single mouse preimplantation embryos. A new ultramicrofluorescence technique developed in our laboratories measures uptake of glutamine in the pmole range. The method will be used to (1) characterize the mechanisms that transport glutamine into and out of the preimplantation embryo, (2) study the action of insulin and related growth factors on the uptake of glutamine, and (3) investigate the possibility of measuring glutamine uptake by preimplantation embryos as a non-invasive test of viability.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD021581-05
Application #
3320534
Study Section
Reproductive Biology Study Section (REB)
Project Start
1986-04-01
Project End
1992-11-30
Budget Start
1990-12-01
Budget End
1991-11-30
Support Year
5
Fiscal Year
1991
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