Decreasing pH of rat embryos and fluids estimated by transplacental distribution of DMO.
Utilizing the transplacental distribution of a weak acid, 5,5-dimethyloxazolidine-2,4-dione (DMO), we have measured the pH of cells within the rat embryo in vivo on days 11.5-14 of gestation. This is a period of rapid organogenesis in this species when the cells of many organ systems begin to change from a proliferative mode into a differentiated state. We found that intracellular pH of the day 11.5 rat embryo is 7.47 +/- 0.03 and decreases steadily to day 14 at which time it reaches 7.11 +/- 0.03. Because there is a concomitant fall in proliferative rate over this span of development, we suggest this correlation to be additional evidence of an association between proliferation and alkalinization of the cell interior. A number of other compartments including embryo plasma, amniotic fluid, exocoelomic fluid, and yolk sac have a decreasing concentration of DMO as development advances, indicative of a steadily declining pH. These changes could have developmental and pharmacokinetic implications.
Collins
M D
MD
Division of Basic Science Research, Children's Hospital Research Foundation, Cincinnati, Ohio 45229-2899.
Duggan
C A
CA
Schreiner
C M
CM
Scott
W J
WJ
D000818:Animals; D001692:Biological Transport; D001826:Body Fluids / Q000378:metabolism*; D001834:Body Water / Q000378:metabolism; D004114:Dimethadione / Q000378:metabolism*; D004210:Dissection; D004622:Embryo, Mammalian / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism; D006400:Hematocrit; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000378:metabolism; D008566:Membranes / Q000378:metabolism; D010080:Oxazoles / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D051381:Rats / Q000097:blood / Q000196:embryology; D011919:Rats, Inbred Strains; D013696:Temperature; D014018:Tissue Distribution
D010080:Oxazoles; D006859:Hydrogen; D004114:Dimethadione