1 3 Arch Toxicol DOI 10.1007/s00204-015-1450-8 INORGANIC COMPOUNDS Expression of basolateral organic anion and cation transporters in experimental cadmium nephrotoxicity in rat kidney Marija Ljubojevic ´ · Davorka Breljak · Carol M. Herak-Kramberger · Naohiko Anzai · Ivan Sabolic ´ Received: 22 July 2014 / Accepted: 6 January 2015 © Springer-Verlag Berlin Heidelberg 2015 Therefore, the diminished renal secretion of OA and OC via PT in Cd nephrotoxicity may result from (a) limited loss of secretory surface (basolateral invaginations), (b) selective loss of Oats and Octs, and (c) loss of cell polarity. Keywords Heavy metal toxicity · Immunocytochemistry · Kidney · Membrane transporters · Organic anions and cations · RT-PCR · SLC22 family · Western blotting Abbreviations BBM Brush border membrane BLM Basolateral membrane Cd Cadmium Cd-NTX Cadmium-induced nephrotoxicity CdMT Cadmium-metallothionein complex Na + /K + -ATPase Sodium-potassium ATPase OA Organic anion OAT/Oat Organic anion transporter OC Organic cation OCT/Oct Organic cation transporter PAH p-Aminohippurate PT Proximal tubule Sglt1 and Sglt2 Sodium-D-glucose cotransporters 1 and 2 TALH Thick ascending limb of Henle TCM Total cell membranes TEA Tetraethylammonium WB Western blotting Introduction In the mammalian kidney, various endogenous and xenobi- otic organic anions (OA) and cations (OC) are eliminated Abstract Cadmium (Cd)-intoxicated experimental animals exhibit impaired renal secretion of organic anions (OA) and cations (OC), indicating their transporters (Oats and Octs) in the proximal tubule (PT) basolateral membrane as possible targets of Cd. To correlate transport data from the literature with the expression of relevant transporters, we performed immunochemical and RT-PCR studies of renal Oats and Octs in the subchronic (treatment with CdCl 2 ; 2 mg Cd/kg b.m./ day, for 2 weeks) and acute (treatment with Cd-metallothio- nein (CdMT); 0.4 mg Cd/kg b.m., 6 or 12 h before killing) models of Cd nephrotoxicity. In the subchronic model, PT exhibited a minor loss of basolateral invaginations and over- all unchanged expression of Na + /K + -ATPase and GAPDH proteins and mRNAs, while the expression of Oat and Oct proteins and their mRNAs was strongly downregulated. In the acute model, a time-related redistribution of basolateral transporters to the intracellular vesicular compartment was a major finding. However, 6 h following CdMT treatment, the total abundance of Oat and Oct proteins in the renal tissue remained unchanged, the expression of mRNAs decreased only for Oats, while a limited Oat1 and Na + /K + -ATPase immunoreactivity in the PT apical membrane indicated loss of cell polarity. As tested in rats treated with colchicine, the observed loss/redistribution of basolateral transport- ers in both models may be independent on microtubules. M. Ljubojevic ´ · D. Breljak · C. M. Herak-Kramberger · I. Sabolic ´ (*) Molecular Toxicology Unit, Institute for Medical Research and Occupational Health, Ksaverska cesta 2, 10000 Zagreb, Croatia e-mail: sabolic@imi.hr N. Anzai Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan