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Nancy Ruddock1 , Zoltan Macháty1 *, Randall Prather1 *
Department of Animal Sciences, University of Missouri, Columbia, Missouri. 1
Significant intracellular pH (pHi) increases accompany parthenogenetic activation of in vitro-matured porcine oocytes using 7% ethanol, 200 µM thimerosal and 50 µM A23187 (calcium ionophore). The objectives of this study were to determine whether these changes in pHi are sodium–dependent, or more specifically due to the amiloride–sensitive Na+/H+ antiport. Intracellular pH was monitored during activation by using the fluorescent pH indicator SNARF–1–AM.
Treatment with 7% ethanol resulted in an average increase in pHi of 0.096±0.007 (n=6). The same treatment in Na+-free medium resulted in a pHi increase of 0.046±0.007 (n=7), and in medium containing 2.5 mM amiloride, an inhibitor of Na+/H+ antiport activity, an increase of 0.028±0.007 (n=7). All treatments were significantly different, P<0.001. Thimerosal treatment resulted in an average pHi increase of 0.798±0.023 (n=8). This increase was not significantly different (P>0.58) from those performed in Na+-free medium (0.763±0.023, n=8), or in medium containing 2.5 mM amiloride (0.774±0.025, n=7). Treatment with 50 µM A23187 resulted in an average increase in pHi of 0.183±0.017 (n=8). This increase in pHi was also not significantly different (P>0.26) from those performed in Na+-free medium (0.144±0.017, n=8), or in medium containing 2.5 mM amiloride (0.158±0.018, n=7). In conclusion, the pHi increase during parthenogenetic activation of porcine oocytes using 7% ethanol is both sodium-dependent and amiloride–sensitive. Activation using 200 µM thimerosal or 50 µM A23187 produces a pHi increase that is sodium–independent, and not affected by amiloride.
This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.