title: Mathematical beta cell model for insulin secretion following IVGTT and OGTT.
abstract: Evaluation of beta cell function is conducted by a variety of glucose tolerance tests and evaluated by a number of different models with less than perfect consistency among results obtained from different tests. We formulated a new approximation of the distributed threshold model for insulin secretion in order to approach a model for quantifying beta cell function, not only for one, but for several different experiments. Data was obtained from 40 subjects that had both an oral glucose tolerance test (OGTT) and an intravenous tolerance test (IVGTT) performed. Parameter estimates from the two experimental protocols demonstrate similarity, reproducibility, and indications of prognostic relevance. Useful first phase indexes comprise the steady state amount of ready releasable insulin A0 and the rate of redistribution krd, where both yield a considerable correlation (both r=0.67) between IVGTT and OGTT estimates. For the IVGTT, A0 correlates well (r=0.96) with the 10 min area under the curve of insulin above baseline, whereas krd represents a new and possibly more fundamental first phase index. For the useful second phase index gamma, a correlation of 0.75 was found between IVGTT and OGTT estimates.
authors.affiliation: Informatics and Mathematical Modelling, Technical University of Denmark, Kongens Lyngby, Denmark. rvo@imm.dtu.dk
authors.forename: Rune V
authors.initials: RV
authors.lastname: Overgaard
authors.forename: Katarina
authors.initials: K
authors.lastname: Jelic
authors.forename: Mats
authors.initials: M
authors.lastname: Karlsson
authors.forename: Jan Erik
authors.initials: JE
authors.lastname: Henriksen
authors.forename: Henrik
authors.initials: H
authors.lastname: Madsen
mesh_terms: D000328:Adult; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D011236:Prediabetic State / Q000175:diagnosis* / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D007328:Insulin; D005947:Glucose