Hi Liliya,

Xenopus oocytes are released in the aquatic environment where they are arguably fine. So considering that the osmotic difference across the plasma membrane should be minimal, my guess is that the intracellular osmolarity is probably not far from the osmolarity of "pond water". This being said, the cytoplasm of the oocyte is far from being homogeneous, so is probably the osmolarity. Is there local changes in the intracellular osmolarity, for example around mitochondria?...  

Hi Norbert,

thank you for your answer.There probably are local changes in the osmolarity as the concentration of calcium in mitochondria proximity can get significantly higher. With that being said ,there should be roughly one baseline value for cytoplasmic osmolarity.From what I found in the literature so far it seems to be around 245mOsm.

Thank you again,

Liliya

Follow this link maybe helpful

Article Osmotic stress stimulates the organic osmolyte channel in Xe...

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