Glucose production during an IVGTT by deconvolution: Validation with the tracer-to-tracee clamp technique

Paolo Vicini, Jeffrey J. Zachwieja, Kevin E. Yarasheski, Dennis M. Bier, Andrea Caumo, Claudio Cobelli

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Abstract

Recently, a new method, based on a two-compartment minimal model and deconvolution [A. Caumo and C. Cobelli. Am. J. Physiol 264 (Endocrinol. Metab.. 37): E829-E841, 1993; P. Vicini, G. Sparacino, A. Caumo, and C. Cobelli. Comput. Meth. Prog. Biomed. 52: 147-156, 1997], has been proposed to estimate endogenous glucose production (EGP) from labeled intravenous glucose tolerance test (IVGTT) data. Our aim here is to compare this EGP profile with that independently obtained with the reference method, based on the tracer- to-tracee ratio (TTR) clamp. An insulin-modified (0.03 U/kg body wt infused over 5 min) [6,6-2H2]glucose-labeled IVGTT (0.33 g/kg of glucose) was performed in 10 normal subjects. A second tracer ([U-13C]glucose) was also infused during the test in a variable fashion to clamp endogenous glucose TTR. The TTR clamp was quite successful. As a result, the EGP profile, reconstructed from [U-13C]glucose data with the models of Steele and Radziuk, were almost superimposable. The deconvolution-obtained EGP profile, calculated from [6,6-2H2]glucose data, showed remarkable agreement with that obtained from the TTR clamp. Some differences between the two profiles were noted in the estimated basal EGP and in the initial modalities of EGP inhibition. A high interindividual variability was also observed with both methods in the resumption of EGP to baseline; variability was high in both the timing and the extent of resumption. In conclusion, the use of the two- compartment minimal model of the IVGTT and deconvolution allows the estimation of a profile of EGP that is in very good agreement with that independently obtained with a TTR clamp.

Original languageEnglish
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume276
Issue number2 39-2
Publication statusPublished - Feb 1999

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Keywords

  • Mathematical model
  • Nonsteady state
  • Specific activity clamp
  • Tracer-to-tracee ratio

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry
  • Physiology (medical)

Cite this

Vicini, P., Zachwieja, J. J., Yarasheski, K. E., Bier, D. M., Caumo, A., & Cobelli, C. (1999). Glucose production during an IVGTT by deconvolution: Validation with the tracer-to-tracee clamp technique. American Journal of Physiology - Endocrinology and Metabolism, 276(2 39-2).