Kidneys of experimental SS rats were perfused to clear them of blood. Kidneys were removed and decapsulated as previously described (31). Briefly, the cortex was isolated, minced in small 1-mm3 pieces, and mechanically strained through steel sieves with different mesh sizes. These procedures were performed in culture medium solution RPMI 1640 (Invitrogen Inc.). Collected glomeruli fractions were obtained by gentle centrifugation. All isolations were performed without the presence of bovine serum albumin to minimize protein contamination. The glomerular fraction contained between 90 and 98% glomeruli. After isolation, both glomeruli and cortical samples, which predominantly consist of tubule fractions, were snap-frozen and later used for metabolomic and proteomic analyses.