title: Relationships of the early insulin secretory response and oral disposition index with gastric emptying in subjects with normal glucose tolerance.
abstract: The oral disposition index, the product of the early insulin secretory response during an oral glucose tolerance test and insulin sensitivity, is used widely for both the prediction of, and evaluation of the response to interventions, in type 2 diabetes. Gastric emptying, which determines small intestinal exposure of nutrients, modulates postprandial glycemia. The aim of this study was to determine whether the insulin secretory response and the disposition index (DI) related to gastric emptying in subjects with normal glucose tolerance. Thirty-nine subjects consumed a 350 mL drink containing 75 g glucose labeled with99mTc-sulfur colloid. Gastric emptying (by scintigraphy), blood glucose (G) and plasma insulin (I) were measured betweent= 0-120 min. The rate of gastric emptying was derived from the time taken for 50% emptying (T50) and expressed as kcal/min. The early insulin secretory response was estimated by the ratio of the change in insulin (∆I0-30) to that of glucose at 30 min (∆G0-30) represented as ∆I0-30/∆G0-30Insulin sensitivity was estimated as 1/fasting insulin and the DI was then calculated as ∆I0-30/∆G0-30× 1/fasting insulin. There was a direct relationship between ∆G0-30and gastric emptying (r= 0.47,P= 0.003). While there was no association of either ∆I0-30(r= -0.16,P= 0.34) or fasting insulin (r= 0.21,P= 0.20), there were inverse relationships between the early insulin secretory response (r= -0.45,P= 0.004) and the DI (r= -0.33,P= 0.041), with gastric emptying. We conclude that gastric emptying is associated with both insulin secretion and the disposition index in subjects with normal glucose tolerance, such that when gastric emptying is relatively more rapid, both the early insulin secretory response and the disposition index are less. These findings should be interpreted as "hypothesis generating" and provide the rationale for longitudinal studies to examine the impact of baseline rate of gastric emptying on the prospective risk of type 2 diabetes.
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia chinmaymarathe@gmail.com.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Chinmay S
authors.initials: CS
authors.lastname: Marathe
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Rayner
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Kylie
authors.initials: K
authors.lastname: Lange
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Michelle
authors.initials: M
authors.lastname: Bound
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Judith
authors.initials: J
authors.lastname: Wishart
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Jones
authors.affiliation: Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Kahn
authors.affiliation: Discipline of Medicine, University of Adelaide Royal Adelaide Hospital, Adelaide, Australia.|Centre of Research Excellence (CRE) in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D005260:Female; D005746:Gastric Emptying / Q000502:physiology*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male
chemical_list: D001786:Blood Glucose; D007328:Insulin
keywords: Gastric emptying; insulin secretory response; oral disposition index; oral glucose tolerance test