title: Residual C-peptide production in type I diabetes mellitus. A comparison of different methods of assessment and influence on glucose control.
abstract: The aims of the present study were to compare various methods for assessment of residual insulin production and to evaluate its role in the metabolic regulation in insulin-dependent, type I diabetes mellitus. Glycosylated hemoglobin (HbA1) was used as a measure of the long-term glycemic control. Twenty-eight patients with type I diabetes mellitus with onset before the age of 30 and with a duration of less than 6 years were studied. C-peptide in plasma in the fasting state, after glucagon stimulation, and the 24-hour urinary excretion were measured. Fasting plasma C-peptide was detected in 61%, and 39% showed a significant rise after glucagon stimulation. The increment correlated negatively with HbA1 (rs = -0.57, p less than 0.001), as did the 24-hour urinary excretion (rs = -0.61, p less than 0.001). The 16 patients with urinary C-peptide values of at least 1 nmol had a mean HbA1 of 8.9 +/- 0.3%, as opposed to 11.6 +/- 0.5% for those excreting less (p less than 0.001). Measurement of the 24-hour urinary excretion of C-peptide provides a reliable method for evaluating residual insulin secretion.
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D002096:C-Peptide / Q000097:blood* / Q000652:urine; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005260:Female; D005934:Glucagon / Q000494:pharmacology; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007328:Insulin / Q000097:blood / Q000627:therapeutic use; D008055:Lipids / Q000097:blood; D008297:Male
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D005934:Glucagon; D006442:Glycated Hemoglobin; D007328:Insulin; D008055:Lipids