Measurement of Glycosylated Haemoglobins and Glycosylated Plasma Proteins in Animal Models with Diabetes or Inappropriate Hypoglycaemia

Summary

Stable glycosylated haemoglobins and glycosylated plasma proteins were determined by affinity chromatography using Glycogel B in animal models with diabetes or inappropriate hypoglycaemia. Adult Aston ob/ob mice and C57BL/KsJ db/db mice exhibited 1.5-1.9 fold increases of body weight, 2.5-3.4 fold elevations of plasma glucose and 20.9-29.3 fold elevations of plasma insulin. Glycosylated haemoglobins and glycosylated plasma proteins were raised 7.2-8.2 fold and 6.6-6.7 fold respectively. In adult NEDH rats, administration of streptozotocin or implantation of transplantable insulinoma fragments produced reciprocal changes in insulin and glucose concentrations either resulting in the onset of insulin deficiency (5.9 fold decrease) and hyperglycaemia (3.2 fold increase) by 2 days, or hyperinsulinaemia (2.1 fold increase) and hypoglycaemia (1.4 fold decrease) by 6 and 8 days, respectively. Glycosylated plasma proteins were increased (1.2 fold) rapidly after streptozotocin treatment followed by glycosylated haemoglobins (1.6 fold increase) after 8 days. In contrast, the decreases in glycosylated plasma proteins and glycosylated haemoglobins (4.4 fold and 1.4 fold, respectively) in insulinoma-bearing rats preceded the demonstration of hypoglycaemia by 5 and 2 days, respectively. Glycosylated plasma proteins in insulinoma-bearing rats returned to pretransplantation values at 10-16 days. Good correlations were observed in mice and rats between glucose and both glycosylated haemoglobins (r = 0.92 and r = 0.90, respectively) and glycosylated plasma proteins (r = 0.85 and r = 0.93), and between the glycosylated blood proteins themselves (r = 0.95 and r = 0.91). The results show that the measurement of glycosylated blood proteins by affinity chromatography using Glycogel B provides a sensitive and reliable indicator of the recent glycaemic environment.

Key-Words

Glycosylated Haemoglobins - Glycosylated Plasma Proteins - ob/ob Mice - db/db Mice - Streptozotocin Diabetic Rats - Insulinoma Bearing Rats - Hypoglycaemia