For the first time membrane anion current activated in response to the cell swelling following exposure to hypotonic solution has been found in human prostate carcinoma cell line LNCaP. The development of hypotonicity-evoked current required 5 to 10 min to the maximum and was almost completely reversible upon return to the solution with normal osmolarity. Not absolute selectivity for Cl- ions of the respective cell volume-sensitive channels has been shown.