Performance of individually measured vs population-based C-peptide kinetics to assess β-cell function in the presence and absence of acute insulin resistance

Ron T. Varghese, Chiara Dalla Man, Marcello C. Laurenti, Francesca Piccinini, Anu Sharma, Meera Shah, Kent R Bailey, Robert A. Rizza, Claudio Cobelli, Adrian Vella

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Aims: To compare the performance of population-based kinetics with that of directly measured C-peptide kinetics when used to calculate β-cell responsivity indices, and to study people with and without acute insulin resistance to ensure that population-based kinetics apply to all conditions where β-cell function is measured. Methods: Somatostatin was used to inhibit endogenous insulin secretion in 56 people without diabetes. Subsequently, a C-peptide bolus was administered and the changing concentrations were used to calculate individual kinetic measures of C-peptide clearance. In addition, the participants were studied on 2 occasions in random order using an oral glucose tolerance test (OGTT). On one occasion, free fatty acid elevation, to cause insulin resistance, was achieved by infusion of Intralipid + heparin. The Disposition Index (DI) was then estimated by the oral minimal model using either population-based or individual C-peptide kinetics. Results: There were marked differences in the exchange variables (k12 and k21) of the model describing C-peptide kinetics, but smaller differences in the fractional clearance; that is, the irreversible loss from the accessible compartment (k01), obtained from population-based estimates compared with experimental measurement. Because it is predominantly influenced by k01, DI estimated using individual kinetics correlated well with DI estimated using population-based kinetics. Conclusions: These data support the use of population-based measures of C-peptide kinetics to estimate β-cell function during an OGTT.

Original languageEnglish (US)
Pages (from-to)549-555
Number of pages7
JournalDiabetes, Obesity and Metabolism
Volume20
Issue number3
DOIs
StatePublished - Mar 1 2018

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Keywords

  • acute insulin resistance
  • C-peptide fractional clearance
  • hepatic insulin extraction
  • insulin action
  • insulin secretion
  • β-cell function

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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