Mechanism of Increased Plasma Glucose Levels after Oral Glucose Ingestion in Normal-Weight Middle-Aged Subjects

Vol. 47, No. 5, 2003

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Original Paper

Mechanism of Increased Plasma Glucose Levels after Oral Glucose Ingestion in Normal-Weight Middle-Aged Subjects
Vincent Rigalleau^a, Michel Beylot^b, Sylvie Normand^c, Christiane Pachiaudi^c, Martine Laville^c, Cyril Petitbois^d, Gérard Deleris^d, Laurence Baillet^a, Henri Gin^a

^aService de Nutrition et Diabétologie, Hôpital Haut-Lévêque, Pessac,
^bINSERM U 499, Faculté de Médecine Laennec, et
^cCentre de Recherche en Nutrition Humaine de Lyon, Lyon, et
^dLaboratoire de chimie bioorganique, Université Victor-Segalen, Bordeaux, France

Address of Corresponding Author

Annals of Nutrition & Metabolism 2003;47:186-193 (DOI: 10.1159/000070484)

Key Words

Age
Glucose tolerance
Substrate competition
Body composition

Abstract

Background/Aims: To determine the decline in glucose tolerance in normal-weight middle-aged subjects, we performed a cross-sectional study using double-labelled oral glucose tolerance tests in 8 middle-aged (46.3 ± 0.9 years) and in 8 young (23.6 ± 0.5) subjects with similar normal body weight. Methods: Plasma glucose was labelled by an infusion of dideuterated glucose started 120 min before ingestion of 1 g/kg of naturally ¹³C-enriched corn starch glucose. Glucose levels, substrate oxidation (indirect calorimetry) and exogenous glucose oxidation (¹³C enrichment of expired CO₂) were monitored for 330 min. Results: In the middle-aged subjects, the appearance of exogenous glucose was reduced (723 ± 52 mg/kg/330 min) compared to young subjects (864 ± 38; p < 0.05), and systemic glucose production was normal. Plasma glucose levels were increased due to a reduced glucose disappearance rate (middle aged: 1,046 ± 61 mg/kg/330 min vs. young 1,242 ± 67; p < 0.05), concerning both oxidative and non-oxidative disposal. This reduction was no longer apparent when the results were normalized for fat-free mass. Insulin levels were similar in young and middle-aged subjects. Conclusion: In normal-weight middle-aged individuals, glucose intolerance is mainly due to the reduction in the mass of fat-free glucose-utilizing tissues. The higher plasma glucose levels enable normal glucose supply to peripheral tissues, and increase splanchnic glucose uptake.

Author Contacts

Dr. V. Rigalleau
Service de Nutrition et Diabétologie, USN, Hôpital Haut-Lévêque
Avenue de Magellan
F-33600 Pessac (France)
Tel. +33 5 56 55 50 78, Fax +33 5 56 55 50 79, E-Mail vincent.rigalleau@wanadoo.fr

Article Information

Received: November 2, 2001
Accepted: October 24, 2002
Number of Print Pages : 8
Number of Figures : 2, Number of Tables : 3, Number of References : 33

Medline Abstract (ID 12748411)

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