Measurement of intracellular pH in sea urchin eggs by 31P NMR

H. Inoue, T. Yoshioka

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


The intracellular pH (pH(i)) of sea urchin eggs was measured using 31P nuclear magnetic resonance (NMR) spectroscopy. The mean value of pH(i) of unfertilized eggs was about 6.2 (H. pulcherrimus and A. crassispina) to 6.3 (P. depressus). In contrast to results of other studies, pH(i) of sea urchin eggs was not changed after fertilization. During exposure of the eggs to NH4Cl or procaine-containing natural sea water (NSW), however, pH(i) rose about 0.4-0.8 pH units; the pH(i) fell to its initial value upon washing the eggs with weak base-free NSW. These changes of pH(i) by weak base treatment agreed well with the data obtained by other workers. In order to understand the discrepancy of pH(i) changes in fertilized eggs between NMR data and other measuring procedures, we measured acid production and O2 uptake, so that CO2 accumulation and proton release did not result in alkalinization. The invariance of the fertilized eggs under anaerobic conditions; otherwise NMR showed a different answer from other measuring procedures, because of its particular characteristics such as non-destructivity and compartmentation of pH.

Original languageEnglish
Pages (from-to)461-468
Number of pages8
JournalJournal of Cellular Physiology
Issue number3
Publication statusPublished - 1980
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology


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