Comparative Metabolic Availability of Glucose and Sucrose and the Effect of Acarbose on Sucrose Utilization During Exercise in Type I Diabetic Patients

Abstract

We have previously shown that glucose (G) and sucrose (S) given orally during exercise of prolonged duration and moderate intensity are perfectly available metabolic substrates. Moreover, in normal humans, we have recently demonstrated that the simultaneous ingestion of 100 mg acarbose (A), an α-glucosidase inhibitor, with 100 g S given at the beginning of such exercise reduces by about 40% the availability of S during exercise [1]. The present study was performed in type I C-peptide negative diabetic patients and aimed at (a) comparing the metabolic availability of 100-g G and S loads and (b) investigating the effect of A on S utilization during exercise. The metabolic and hormonal responses thereby induced were also analyzed. Six overnight fasted, young diabetic subjects, accustomed to physical exercise and well controlled by continuous subcutaneous insulin infusion (CSII), were exercised for 240 min on a treadmill (about 40% VO_2max) in three randomized experimental conditions, 1–2 weeks apart: they drank at 0, 60, 120, and 180 min 4 × 25 g (0.25 g/ml water) of either G, S or S+A (4 × 15 mg). “Naturally labeled” [¹³C]glucose or sucrose were used in order to follow by isotope radio-mass spectrometry the conversion to expired air CO₂ of the sugar ingested. In each test, CSII was interrupted at time −15 min.