title: Two-hour seven-sample oral glucose tolerance test and meal protocol: minimal model assessment of beta-cell responsivity and insulin sensitivity in nondiabetic individuals.
abstract: Highly informative yet simple protocols to assess insulin secretion and action would considerably enhance the quality of epidemiological and large-scale clinical trials. In an effort to develop such protocols, a 5-h, 11-sample oral glucose tolerance test (OGTT) was performed in 100 individuals and a 7-h, 21-sample meal in another 100. Plasma glucose, insulin, and C-peptide concentrations were measured. We show that virtually the same minimal model assessment of beta-cell responsivity (dynamic [Phi(d)] and static [Phi(s)]), insulin sensitivity (Si), and disposition index (DI) can be obtained with a reduced seven-sample 2-h protocol: Phi(d), reduced versus full: 871.50 vs. 873.32, r = 0.98 in OGTT and 494.88 vs. 477.99 10(-9), r = 0.91 in meal; Phi(s): 42.36 vs. 44.35, r = 0.88 in OGTT and 35.31 vs. 35.37 10(-9) min(-1), r = 0.90 in meal; Si: 24.33 vs. 22.77 10(-5) dl x kg(-1) x min(-1) per pmol/l, r = 0.89 in OGTT and 19.03 vs. 19.77 10(-5) dl x kg(-1) x min(-1) per pmol/l, r = 0.85 in meal; and DI: 1,282.26 vs. 1,273.23, r = 0.84 in OGTT and 726.92 vs. 776.97 10(-14) dl . kg(-1) x min(-2) per pmol/l, r = 0.84 in meal. This reduced protocol will facilitate the study of insulin secretion and action under physiological conditions in nondiabetic humans.
authors.affiliation: Department of Information Engineering, University of Padova, Padova, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Dalla Man
authors.forename: Marco
authors.initials: M
authors.lastname: Campioni
authors.forename: Kenneth S
authors.initials: KS
authors.lastname: Polonsky
authors.forename: Rita
authors.initials: R
authors.lastname: Basu
authors.forename: Robert A
authors.initials: RA
authors.lastname: Rizza
authors.forename: Gianna
authors.initials: G
authors.lastname: Toffolo
authors.forename: Claudio
authors.initials: C
authors.lastname: Cobelli
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000378:metabolism; D004032:Diet; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D007333:Insulin Resistance / Q000502:physiology; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism*; D008875:Middle Aged; D008954:Models, Biological; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin