Ion compartmentalization in frog oocytes as demonstrated by X-ray microanalysis.
The distributions of K, Na, Mg and Ca within frog ovarian and oviductal oocytes were studied by electron probe wavelength dispersive X-ray microanalysis. An important heterogeneity could be found both in nuclear and jelly coated oocytes. The highest K, Mg and, to a lesser extent, Na concentrations were found in the pigmented area of the peripheral cytoplasm. There is a certain correlation between the distribution of K and Mg. The concentration of K (but not of Na) in the nucleus was higher than that in the non-pigmented cytoplasm. The distribution of Ca was rather uniform. The high amounts of K, Na and S determined in the oocyte jelly coat seem to have become accumulated by ion-exchange mechanism. Oocyte pigment granules are believed to be the site of ion compartmentalization and to play a role in regulation of intracellular ionic composition.
D000818:Animals; D002118:Calcium / Q000032:analysis*; D002451:Cell Compartmentation; D003594:Cytoplasmic Granules / Q000032:analysis; D004577:Electron Probe Microanalysis; D005260:Female; D008274:Magnesium / Q000032:analysis*; D008543:Melanins / Q000032:analysis; D009865:Oocytes / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis; D011188:Potassium / Q000032:analysis*; D011896:Rana temporaria; D012621:Seasons; D012964:Sodium / Q000032:analysis*; D013455:Sulfur / Q000032:analysis
D008543:Melanins; D010758:Phosphorus; D013455:Sulfur; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium