SELECTIVE DETERMINATION OF NONENZYMATIC GLYCOSYLATED SERUM-ALBUMIN ASA MEDIUM-TERM INDEX OF DIABETIC CONTROL

Serum proteins are non-enzymatically glycosylated dependent on the con centration of free glucose and measurements of their concentration are used to control diabetic carbohydrate metabolism. Eight patients with insulin-dependent diabetes mellitus (IDDM) and 8 patients with non-in sulin-dependent diabetes mellitus (NIDDM) with glycosylated hemoglobin levels of at least 10.5% were studied during a 6-week period of antid iabetic therapy. Glycosylated serum albumin (GSA) and glycosylated tot al serum proteins (GSP) were measured weekly using an affinity chromat ography procedure. The fructosamine test (FA) and the measurement of m ean blood glucose (MBG) were also carried out weekly. Glycosylated hem oglobin and its glucose adduct HbA1c were determined at 14-day interva ls (HPLC-method). All measured parameters decreased during the period of the study. The correlation coefficients for the glycosylated protei ns versus the MBG determined one week earlier were highest for GSA [ID DM: r(GSA/MBG-1) = 0.726, p<0.001 for the single values and 0.984, p<0 .001 for the mean values; NIDDM: r (GSA/MBG-1) = 0.636, p<0.001 for th e single values and 0.986, p<0.001 for the mean values]. The differenc es between the IDDM and NIDDM group probably occurred because 6 NIDDM patients were taking glibenclamide (7.0-10.5 mg/day) which is known to inhibit the glycosylation reaction of albumin. The fructosamine test is more prone to interferences than the selective determination of GSA . GSA determination therefore, gives precise data in medium term diabe tic control.