Antibodies against a furosemide binding protein from Ehrlich ascites tumour cells inhibit Na+, K+, Cl− co‐transport in frog retinal pigment epithelium

Open Access
Publisher Website
Google Scholar
Abstract
Purpose: To investigate whether antibodies against a 100 kDa protein purified by furosemide affinity chromatography from Ehrlich ascites tumour cells could inhibit Na+, K+, Cl− co-transport in the isolated frog retinal pigment epithelium. Methods: The rate of Na+, K+, Cl− co-transport across the retinal membrane in the isolated frog RPE preparation was measured as the rate of decrease in the intracellular Cl− activity observed after administration of furosemide in the apical bath. The intracellular Cl− activity was measured with double barrelled Cl− sensitive microelectrodes. Results: Incubation of frog retinal pigment epithelium for 30 min with antibodies reduced the rate of Na+, K+, Cl− co-transport by 43%, while leaving all other measured electrophysiological parameters intact. Conclusion: The antibodies inhibit Na+, K+, Cl− co-transport in the frog retinal pigment epithelium. This could be due to binding of the antibodies to the co-transporter itself or to a regulatory protein.