Role of calcium in regulating intracellular pH following the stepwise release of the metabolic blocks at first-meiotic prophase and second-meiotic metaphase in amphibian oocytes

Progesterone-induced changes in the phosphoryl potential during the meiotic divisions in amphibian oocytes: Role of Na/K-ATPase

“…Use of the convolution difference technique alone (lower spectrum, Figure 2) is useful for resolving creatine phosphate, and the α, β, and γ resonances of ATP, although insufficient to resolve the P i peak. Techniques based on differential relaxation properties of the narrow P i resonance have been used for observing and defining the position of the intracellular P i resonance [6]. Saturation transfer experiments were carried out by application of a low power RF pulse for a time of 3T 1 to either the γATP or PCr resonance.…”

“…Oocytes from each female undergo synchronous meiotic divisions. The prophase-arrested (control) oocytes maintain a sizeable pool of high energy phosphate compounds, including phosphocreatine (PCr), ATP and serine-rich phosphoproteins, for at least 24 h during superfusion [6]. …”

31P Nuclear Magnetic Resonance Studies on the Phosphorus-Containing Metabolites of the Developing Embryos of a Freshwater Catfish, Clarias batrachus (L.)

“…It was observed that the intracellular pH increased by 0.04 units following fertilization and remained so till the gastrula stage, after which it declined by 0.06 units. Earlier studies had indicated that in frog following fertilization, intracellular pH increased by 0.5 to 0.6 units (Morrill et al, 1984), whereas in Xenopus and crab the increase observed was only 0.24 and 0.13 units, respectively (Nuccitelli et al, 1981;Goudeau et al, 1989); moreover, in sea urchin eggs, the pH remained constant even following fertilization (Inoue and Yoshioka, 1980). The molecular mechanism underlying the increase in intracellular pH following fertilization is not known, but such increases were also observed following treatment of eggs with progesterone or insulin, which are known to increase intracellular Ca 2+ and Na + (Morrill et al, 1984.…”

“…Earlier studies had indicated that in frog following fertilization, intracellular pH increased by 0.5 to 0.6 units (Morrill et al, 1984), whereas in Xenopus and crab the increase observed was only 0.24 and 0.13 units, respectively (Nuccitelli et al, 1981;Goudeau et al, 1989); moreover, in sea urchin eggs, the pH remained constant even following fertilization (Inoue and Yoshioka, 1980). The molecular mechanism underlying the increase in intracellular pH following fertilization is not known, but such increases were also observed following treatment of eggs with progesterone or insulin, which are known to increase intracellular Ca 2+ and Na + (Morrill et al, 1984. Van den Thillart and Van Waarde (1996) suggest that the cytoplasmic alkalination observed in eggs after fertilization may be due to the close relationship between intracellular pH and metabolic rate since the pH is low in nondividing eggs but is known to increase as soon as the egg is triggered into division following fertilization.…”

“…31 P NMR studies in vertebrates for obvious reasons could be undertaken only in those animals in which fertilization and development is external and in embryos that are not too big to be analyzed inside the NMR tube. Because of these limitations 31 P NMR has so far been used only to study the developing embryos of amphibians with respect to changes in phosphometabolite concentrations and intracellular pH following fertilization and development (Nuccitelli et al, 1981;Morrill et al, 1984Morrill et al, , 1985Gupta et al, 1985). Similar studies using 31 P NMR should also be possible in fish because the embryos are small, they can develop to an advanced stage (fry) in distilled water, they are available in plenty, and are viable in the NMR tube.…”