Correlations between fasting plasma C-peptide, glucagon-stimulated plasma C-peptide, and urinary C-peptide in insulin-treated diabetics

Diabetes Care. 1987 Jul-Aug;10(4):487-90. doi: 10.2337/diacare.10.4.487.

Abstract

This study correlated fasting plasma C-peptide (CP), plasma CP 6 min after stimulation with 1 mg glucagon i.v., and the mean of three 24-h urinary excretions of C-peptide (UCP)/creatinine in 132 insulin-treated diabetics. Patients were divided into three groups: group 1, stimulated CP less than 0.06 nM (n = 51); group 2, stimulated CP 0.06-0.60 nM (n = 48); and group 3, stimulated CP greater than 0.60 nM (n = 33). In all patients fasting CP was closely correlated to stimulated CP (r = .988, P less than .001), whereas the correlations between UCP and both fasting CP (r = .904, P less than .001) and stimulated CP r = .902, P less than .001) were slightly less pronounced. The associations between UCP and both fasting CP (r = .716, P less than .001) and stimulated CP (r = .731, P less than .001) were modest in group 2, and even more so in group 3 (r = .557, P less than .001 and r = .641, P less than .001, respectively). In conclusion, fasting CP is closely correlated to glucagon-stimulated CP in insulin-treated diabetics and can probably be used equally well in the assessment of beta-cell function. The associations between UCP and both fasting and glucagon-stimulated CP are less pronounced, especially in patients with well-preserved beta-cell function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • C-Peptide / blood
  • C-Peptide / metabolism*
  • C-Peptide / urine
  • Diabetes Mellitus, Type 1 / metabolism*
  • Fasting
  • Female
  • Glucagon*
  • Humans
  • Islets of Langerhans / physiopathology*
  • Male
  • Middle Aged

Substances

  • C-Peptide
  • Glucagon