1983 Volume 26 Issue 9 Pages 931-939
In order to evaluate the significance of residual B-cell function in determining blood glucose instability in 24 insulintreated diabetic patients, the relation between serum C-peptide secretory capacity in response to 50 g oral glucose load and the standard deviation (SD) of the mean blood glucose (MBG) level or the M value obtained from the diurnal blood glucose curve was examined. The C-peptide immunoreactivity (CPR) of sera after polyethylene glycol precipitation (free-CPR) was assayed in determining the residual B-cell function. 125I-insulin binding to insulin antibody in the patient's serum was determined by the ethanol precipitation method.
In all insulin-treated diabetic patients, fasting free-CPR, Σfree-CPR and free-CPR response (peakfasting free-CPR) during glucose load were 1.0±0.1 (M±SE), 7.1±0.9 and 0.8±0.1 ng/ml, respectively. The SD of the MBG level and M value were 59±4 mg/dl and 43.9±6.0, respectivey. No significant difference was noted in these values in the presence or absence of insulin antibody.
A significant negative correlation was observed between fasting free-CPR, Σfree-CPR or free-CPR response and the SD of the MBG level (p<O.01, p<O.01 and p<O.05, respectively). A similar significant negative correlation was noted between each parameter of free-CPR and the M value (p<O.05).
Patients with an M value of more than 43 (n=11) were significantly younger (p<0.05). their MBG levels and SD were significantly larger (p<0.01 and p<0.005, respectively) and fasting free-CPR, I free CPR and free-CPR response were significantly lower (p<0.05, p<0.01 and p<0.05, respectively) than those in patients with an M value of within 43 (n =13).
There was no significant correlation between either the SD of the MBG level or the M value and 125I-insulin binding in patients with insulin antibody.
These results suggest that instability of blood glucose depends upon the residual B-cell secretory capacity, but not the presence of insulin antibody.
