Isolation of Glomerula from Rat Kidney

IN contrast to the renal tubular system the glomerulum has not received as much attention biochemically as it deserves. This is mostly due to the difficulties in isolating a pure glomerular fraction. Only during the past ten years have a few methods been worked out which are, however, too complicated and time-consuming for the study of enzyme patterns in single normal or diseased animals. McCann's method 1 , using manually isolated glomerula from frozen-dried sections, is limited by the small amount of tissue available for analysis. To obtain larger samples, attempts have been made to isolate the glomerula from crude kidney homogenate. Liberation of the glomerula from surrounding tissue was achieved by using a Potter–Ervenjem tissue homogenizer 2 with a mismatched plunger 3 or pushing the kidney through a fine-meshed wire gauze 4–8 . The purification of the glomerular fraction was performed either by repeated centrifugation 4 , by filtration through a layer of glass balls 7 , or by magnetic attraction following intra-arterial injection of iron trapped in the glomerula 8 . No detailed information on purity or yield of the glomerula was given. For enzyme work on normal and diseased glomerula a method had to be developed allowing rapid, and technically simple, isolation.