title: Urinary C-peptide: a useful tool for evaluating the endogenous insulin reserve in cohort and longitudinal studies of diabetes in childhood.
abstract: Increasing research into the remission phase of type I diabetes mellitus stresses the importance of a non-traumatic and reliable method for the evaluation of endogenous insulin production. We compared 24-h urinary C-peptide excretion (UCE) with plasma C-peptide values before and after stimulation with 1 mg glucagon in 24 type I diabetic children. Fasting plasma C-peptide values and stimulated plasma C-peptide values showed a linear correlation with 24 h UCE. Mean plasma C-peptide levels correlated inversely with the exogenous insulin dose. A slightly better correlation was found between the exogenous insulin dose and 24 h UCE. Control data of 24 h UCE were obtained from healthy siblings. A linear correlation with age was found up to 10 years of age above which UCE values seem to reach a plateau. This effect of age, as well as the frequency of sampling was taken into account in the derivation of 95% reference intervals for UCE. The measurement of 24 h UCE appears to be a useful parameter to assess endogenous insulin production in diabetic children, provided that age is taken into account.
authors.affiliation: Department of Pediatrics, Erasmus University, Rotterdam, The Netherlands.
authors.forename: C E
authors.initials: CE
authors.lastname: de Beaufort
authors.forename: N C
authors.initials: NC
authors.lastname: den Boer
authors.forename: G J
authors.initials: GJ
authors.lastname: Bruining
authors.forename: G A
authors.initials: GA
authors.lastname: Eilers
authors.forename: R
authors.initials: R
authors.lastname: van Strik
authors.forename: T
authors.initials: T
authors.lastname: Weterings
mesh_terms: D002096:C-Peptide / Q000097:blood / Q000652:urine*; D002648:Child; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy / Q000652:urine*; D005934:Glucagon; D006029:Glycosuria; D006801:Humans; D007328:Insulin / Q000502:physiology* / Q000627:therapeutic use; D007657:Ketone Bodies / Q000097:blood; D008137:Longitudinal Studies
chemical_list: D002096:C-Peptide; D007328:Insulin; D007657:Ketone Bodies; D005934:Glucagon