Specific radioimmunoassay of glucitol-lysine--application to lens proteins in streptozotocin-diabetic rats.

A radioimmunoassay using antibody against glucitol-lysine was developed to quantitate glycated proteins in the lens of diabetic rats. The amount of glycated protein was expressed as molar equivalents of reduced glycated hippuryl lysine (GlcRED-Hip-Lysine). Significant differences (p less than 0.01) were found in the amounts of glycated protein in the lenses of rats with streptozotocin-induced diabetes (3.92 +/- 0.59 nmol/mg protein, n = 5), those with streptozotocin-induced diabetes treated with insulin (2.94 +/- 0.36 nmol/mg protein, n = 4) and normal rats (1.23 +/- 0.22 nmol/mg protein, n = 5). There was a significant correlation between the concentration of glycated protein in the lens and the HbA1c level at the end of the 12 week experiment (r = 0.957, p less than 0.001). These results indicate that glycation of lens protein is parallel with the severity of diabetes in rats.