Analysis of urinary albumin, transferrin, N-acetylβ-D-glucosaminidase and β2-microglobulin in patients with impaired glucose tolerance

We investigated the changes in urinary albumin and urinary transferrin as glomerular proteins, and in urinary N-acetyl-β-D-glucosaminidase and urinary β2-microglobulin as tubular proteins, in patients with impaired glucose tolerance. We attempted to compare the proteins of normal subjects to those of diabetics with pre-nephropathy. Transferrin and N-acetyl-β-D-glucosaminidase levels were significantly increased in patients with impaired glucose tolerance, while albumin and β2-microglobulin levels were only slightly increased. In addition, there was no significant difference in transferrin levels between patients with impaired glucose tolerance and type 2 diabetics with pre-nephropathy. In our observation, although albumin levels were only slightly increased in patients with impaired glucose tolerance, a sharp increase in transferrin levels was reflected in patients with glomerular disorders. In addition, since N-acetyl-β-D-glucosaminidase levels varied markedly, tubular disorders were suspected. It should be stressed that increased parameters for both glomerular and tubular disorders in group C—patients who showed abnormal levels in three proteins—had already been observed in some patients with impaired glucose tolerance. Therefore, the evaluation of the mutual relationships between various urinary protein components in patients with impaired glucose tolerance will become a more important assessment tool than that of single urinary protein components. J. Clin. Lab. Anal. 12:351–355, 1998. © 1998 Wiley-Liss, Inc.