DETERMINATION OF GLYCATED HEMOGLOBINS IN THE RAT - COMPARISON BETWEEN2 DIFFERENT CHROMATOGRAPHIC METHODS AND APPLICATION IN EXPERIMENTAL DIABETOLOGY

Due to the unusual presence of several different hemoglobin components in the rat, determination of glycated hemoglobin (Hb) has been consid ered difficult and often unreliable in this animal species. In the pre sent study, we compare a fully automated high-performance liquid chrom atographic (HPLC) method of analysis of glycated hemoglobin that has b een assessed for clinical use with an affinity chromatography techniqu e using boronate micro-columns; we used blood samples taken from Sprag ue-Dawley rats of various ages and streptozotocin-diabetic rats. In no ndiabetic rats, the sum of HbA(1c) and other minor glycated hemoglobin s separated by the HPLC method is close to the total glycated hemoglob in obtained by affinity chromatography for each age group of animals. In diabetic rats, the glycated hemoglobins measured by whatever method show a linear increase during the first 3 weeks following streptozoto cin administration, with the difference that glycated hemoglobin value s obtained by affinity chromatography are markedly higher than those o btained by HPLC technique. Interestingly, a comparative determination of glycated hemoglobin in diabetic patients gives the same results wit h both methods. Therefore, it appears that in the rat, unlike man, at high glucose concentrations glycation occurs preferentially at the ami no groups of hemoglobin components, which are not separated by the HPL C method. Our results indicate that while affinity chromatography shou ld be used to detect the total extent of hemoglobin glycosylation in d iabetic rats, the utilization of rapid and automatized HPLC procedures can be a very convenient alternative for the determination of glycate d hemoglobin in both euglycemic and hyperglycemic rats.