Diurnal Pattern to Insulin Secretion and Insulin Action in Healthy Individuals
- Ahmed Saad1,
- Chiara Dalla Man2,
- Debashis K. Nandy1,
- James A. Levine1,
- Adil E. Bharucha1,
- Robert A. Rizza1,
- Rita Basu1,
- Rickey E. Carter3,
- Claudio Cobelli2,
- Yogish C. Kudva1 and
- Ananda Basu1⇓
- 1Division of Endocrinology and Metabolism, Mayo College of Medicine, Rochester, Minnesota
- 2Department of Information Engineering, University of Padova, Via Gradenigo 6B, Padova, Italy
- 3Department of Health Sciences Research, Mayo College of Medicine, Rochester, Minnesota
- Corresponding author: Ananda Basu, .
A.S., C.D.M., and D.K.N. contributed equally to this study.
Evaluation of the existence of a diurnal pattern of glucose tolerance after mixed meals is important to inform a closed-loop system of treatment for insulin requiring diabetes. We studied 20 healthy volunteers with normal fasting glucose (4.8 ± 0.1 mmol/L) and HbA1c (5.2 ± 0.0%) to determine such a pattern in nondiabetic individuals. Identical mixed meals were ingested during breakfast, lunch, or dinner at 0700, 1300, and 1900 h in randomized Latin square order on 3 consecutive days. Physical activity was the same on all days. Postprandial glucose turnover was measured using the triple tracer technique. Postprandial glucose excursion was significantly lower (P < 0.01) at breakfast than lunch and dinner. β-Cell responsivity to glucose and disposition index was higher (P < 0.01) at breakfast than lunch and dinner. Hepatic insulin extraction was lower (P < 0.01) at breakfast than dinner. Although meal glucose appearance did not differ between meals, suppression of endogenous glucose production tended to be lower (P < 0.01) and insulin sensitivity tended to be higher (P < 0.01) at breakfast than at lunch or dinner. Our results suggest a diurnal pattern to glucose tolerance in healthy humans, and if present in type 1 diabetes, it will need to be incorporated into artificial pancreas systems.
This article contains Supplementary Data online at http://diabetes.diabetesjournals.org/lookup/suppl/doi:10.2337/db11-1478/-/DC1.
- Received October 20, 2011.
- Accepted April 24, 2012.
- © 2012 by the American Diabetes Association.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.