Role of the low-selective organic anion transport in regulation of osmotic balance of renal collecting duct principal cells under hypo-osmotic conditions.

In the course of adaptation of the rat kidney collecting duct cells to hypo-osmotic medium, the organic anion transporter inhibitor probenecid reduced significantly the regulatory cell volume decrease in response to a hypotonic shock. Both probenecid and hypotonic shock delayed significantly the entry into a cell of the fluorescent dye calcein, which exists as anion at neutral pH. Thus, the organic osmolyte transport plays an important role in the regulatory decrease of the principal cell volume under the hypo-osmotic conditions.