Residual beta cell function in insulin-dependent diabetes: evaluation by circadian determination of C-peptide immunoreactivity.

Residual beta cell function was evaluated through circadian determination of C-peptide immunoreactivity (CPR) in eighty insulin-dependent diabetics. Evaluation of beta cell activity through circadian CPR determination was in good agreement with the results obtained by glucagon test which is considered a potent stimulus of C-peptide release. The prevalence of residual beta cell function in our population was 35%. Residual beta cell function was associated with a shorter duration of diabetes, a lower dose of insulin therapy and less chronic complications. On the other hand, serum growth hormone circadian variations were more spread in diabetics without beta cell function. That is consistent with diabetes instability which has been reported more commonly insulin-dependent diabetics without beta cell function.