Decreasing pH of rat embryos and fluids estimated by transplacental distribution of DMO

• Published in: The American journal of physiology Vol. 257; no. 3 Pt 2; p. R542
• Main Authors: Collins, M D, Duggan, C A, Schreiner, C M, Scott, Jr, W J
• Format: Journal Article
• Language: English
• Published: United States 01.09.1989
• Subjects: Animals; Biological Transport; Body Fluids - metabolism; Body Water - metabolism; Dimethadione - metabolism; Dissection; Embryo, Mammalian - metabolism; Extracellular Space - metabolism; Hematocrit; Hydrogen - metabolism; Hydrogen-Ion Concentration; Intracellular Membranes - metabolism; Membranes - metabolism; Oxazoles - metabolism; Placenta - metabolism; Rats - blood; Rats - embryology; Rats, Inbred Strains; Temperature; Tissue Distribution
• ISSN: 0002-9513
• DOI: 10.1152/ajpregu.1989.257.3.R542

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.