Elevation rate of glycosylated hemoglobins in dogs after induction of experimental diabetes mellitus.

The glycosylated hemoglobin, hemoglobin A1c, (HbA1c), which reflects average plasma glucose of the previous few weeks, has recently been used to monitor humans with diabetes mellitus. Further understanding of the HbA1c elevation rate would improve interpretation of HbA1c. We determined glycosylated hemoglobin elevation rates in 5 dogs with induced diabetes. Hemoglobin A1C was determined by an established column chromatographic technique; plasma glucose by glucose oxidase. Values were determined on 13 normal dogs and compared with values obtained weekly from surgically or chemically induced diabetic dogs. Hemoglobin A1c increased in a fashion that could be predicted by modelling. The model predicts that large changes in Hb A1c will occur within the first few weeks of a sudden change in glucose and that a new plateau will be reached at a time equal to the erythrocyte life span. In the present experiment abnormally elevated HbA1c occurred after 2 wk of hyperglycemia. The results should approximate the elevation rate after acute onset and sustained severe hyperglycemia in humans, because humans and canine are hematologically similar and thus extend previously reported studies on human out-patient diabetics.