In this paper the domain of validity of the unlabelled and labelled minimal models of glucose disappearance is studied. Labelled intravenous glucose tolerance tests were performed in six normal subjects using 3-3H-glucose as the tracer. Insulin and unlabelled glucose data were analysed with the minimal model of glucose disappearance. The model provides estimates of glucose effectiveness (SG) and insulin sensitivity (SI) which measure the effects of glucose per se and insulin on both glucose production and disposal. Insulin and labelled glucose data were analysed with the labelled minimal model of tracer disappearance. Estimates of glucose effectiveness (SG*) and insulin sensitivity (SI*) which reflect disposal processes only were calculated. The results of the two minimal models suggest two areas of model error. Firstly, the relationships between labelled and unlabelled parameters contradict the theoretical expectation. Secondly, the time-course of hepatic glucose production is unrealistic. Possible sources of these inconsistencies are an inadequate description of the glucose and/or insulin effect upon hepatic glucose production, and the assumption that glucose kinetics are monocompartmental. The monocompartmental description of glucose kinetics may affect both model parameters and hepatic glucose production and this leads to a critical reexamination of the previously published validation studies in which the minimal model metabolic indices have been compared with the analogous indices measured during glucose clamp studies.
|Titolo:||Minimal models of glucose disappearance : lessons from the labelled IVGTT|
CAUMO, ANDREA (Primo)
|Parole Chiave:||glucose clearance; insulin sensitivity; IVGTT; mathematical model|
|Settore Scientifico Disciplinare:||Settore ING-INF/06 - Bioingegneria Elettronica e Informatica|
|Data di pubblicazione:||nov-1991|
|Digital Object Identifier (DOI):||10.1111/j.1464-5491.1991.tb02120.x|
|Appare nelle tipologie:||01 - Articolo su periodico|