Abstract: AIM: To study the effect of hydrocortisol on regulatory volume decrease (RVD)in Jurkat cells and its possible mechanism. METHODS: The measurement of Jurkat cell volume was performed under the microscope and the imaging analysis which was carried out by Motic Images Advanced 3.1 Software.The cell proliferation was measured with 3H-TdR incorporation. RESULTS: Hydrocortisol (10^-4 and 10^-3 mol·L^-1)inhibited RVD in Jurkat cells with dose dependent manner.A potassium channel blocker (quinine)was also found to have an inhibition to Jurkat cell RVD.The Jurkat cell proliferation (including with and without Con A)was significantly suppressed by hydrocortisol (10^-3 mol·L^-1)and quinine (10^-3 mol· L^-1). CONCLUSION: The inhibition of Jurkat cell RVD induced by hydrocortisol might be from the inhibition of potassium channel.

Key words: hydrocortisol, Jurkat cell, regulatory volume decrease, potassium channel blocker, lymphocyte proliferation