New potent inhibitors of aquaporins: silver and gold compounds inhibit aquaporins of plant and human origin.

Silver and gold compounds were tested as potential inhibitors of aquaporins of plant- and human origin. Silver as AgNO(3) or silver sulfadiazine inhibited with high potency (EC(50) 1-10 microM) the water permeability of the peribacteroid membrane from soybean (containing Nodulin 26), the water permeability of plasma membrane from roots (containing plasma membrane integral proteins), and the water permeability of human red cells (containing aquaporin 1). Gold as HAuCl(4) was less effective but still inhibited peribacteroid membrane water permeability (EC(50)=10 microM). Silver and gold are more potent inhibitors of aquaporins than the presently widely used mercury containing compounds.