Rabbit glomerular and tubular basement membranes: morphology and differential solubilization

Rabbit glomeruli and tubules were obtained by retrograde perfusion of magnetite into the lower aorta as previously described for the isolation of rat glomeruli. In addition, an alternative method of separating rabbit glomerular and tubular basement membranes from a single renal cortex preparation was developed. These preparations, which represent the Triton X-100-insoluble material, were extracted in sequence with deoxycholate, dodecyl sulfate in the presence and absence of 2-mercaptoethanol at 8 degrees C and again in the latter at 100 degrees C. The polypeptides solubilized at each step of this sequence were characterized by electrophoresis. The final extract consisted almost exclusively of red-staining, presumably collagenous bands, while the earlier extracts consisted of blue-staining, presumably noncollagenous bands. No significant differences were found between the glomerular and tubular basement membrane extracts.