Biochemical alterations of the human glomerular basement membrane in diabetes.

Only from the kidney glomerulus can the capillary basement membrane be isolated in quantities sufficient for biochemical analyses. In this study an attempt has been made to obtain a basement membrane as pure as possible, without contamination from cells or mesangium. In diabetic nephropathy, the glomerular basement membrane shows a decreased content of cystine, but hydroxylysine concentrations was only slightly higher than in normal material. The concentration of glucose was significantly increased. Immunofluorescent studies indicated the presence of serum proteins in the diabetic glomerular basement membrane, probably as a result of increased membrane permeability.