[C-peptide excretion in 24 hours-urine as an indicator of B-cell residual function in children and adolescents with type-I-diabetes (author's transl)].

In 140 juvenile diabetics residual B-cell-function was measured according to the amount of the immunoreactive C-peptide (IRCP) in the 24 h-urine. We were able to repeat this test after two years in 69 of these patients. All diabetic children showed maintained residual insulin secretion (mean +/- S mean 2.60 +/- 0.31 nmol/24 h). There was a significant negative relationship (p less than 0.001) between the duration of diabetes and the extend of the residual B-cell-function. C-peptide urine excretion of the diabetics who were followed up dropped significantly (0.08 down to 0.02 nmol/kg/24 h, p less than 0.001), and the daily insulin requirement increased significantly (0.36 to 0.67 U/kg, p less than 0.05). In comparison, children with a shorter duration of the diabetes (less than 3 years) showed a more rapid decrease of their residual B-cell function with a simultaneously greater increase of the daily insulin dose as opposed to children with the diabetes for longer than 3 years at the time when they were first seen. With a short course of diabetes the decrease of the C-peptide and the increase of the daily insulin dose were negatively correlated (p less than 0.001). The clinical phenomena of the remission period as known until now are related to the decline of B-cell function.