Utilization of oral sucrose load during exercise in humans. Effect of the alpha-glucosidase inhibitor acarbose.
We investigated the hormonal and metabolic response to a 100-g sucrose load given 15 min after adaptation to moderate-intensity (50% VmaxO2) long-duration (4-h) exercise in healthy volunteers. The effect of a 100-mg dose of the alpha-glucosidase inhibitor Acarbose ingested with the sucrose load was also investigated. "Naturally labeled [13C] sucrose" was used to follow the conversion to expired-air CO2 of the sugar ingested by isotope-ratio mass spectrometry. Circulating hormone and metabolite data were obtained in nine subjects, and indirect calorimetry and stable isotope methodology were applied to six of them. Under placebo, 93 +/- 4 g sucrose were entirely oxidized during the 4 h of exercise, total carbohydrate utilization was 235 +/- 14 g, endogenous carbohydrate utilization was 142 +/- 13 g, and total lipid oxidation was 121 +/- 7 g. A single oral dose of 100 mg Acarbose ingested with the sucrose load did not significantly modify total carbohydrate (239 +/- 2 g/4 h) or lipid (122 +/- 6 g/4 h) oxidation. In contrast, sucrose oxidation was reduced to 53 +/- 6 g/4 h and endogenous carbohydrate utilization increased to 186 +/- 7 g/4 h. Reduction of the rises in blood glucose and fructose and of the increases in plasma insulin and C peptide under Acarbose confirmed these effects, whereas lower circulating levels of alanine suggested a higher rate of gluconeogenesis. These data show that a 100-g glucose load ingested soon after initiation of exercise is a perfect available metabolic substrate.(ABSTRACT TRUNCATED AT 250 WORDS)
D020909:Acarbose; D000328:Adult; D000409:Alanine / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005632:Fructose / Q000097:blood; D005990:Glycerol / Q000097:blood; D065089:Glycoside Hydrolase Inhibitors; D006801:Humans; D007328:Insulin / Q000097:blood; D007773:Lactates / Q000097:blood; D008297:Male; D009638:Norepinephrine / Q000097:blood; D005082:Physical Exertion / Q000187:drug effects*; D012119:Respiration / Q000187:drug effects; D013395:Sucrose / Q000378:metabolism*; D014312:Trisaccharides / Q000494:pharmacology*
D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D065089:Glycoside Hydrolase Inhibitors; D007328:Insulin; D007773:Lactates; D014312:Trisaccharides; D005632:Fructose; D013395:Sucrose; D000409:Alanine; D005990:Glycerol; D020909:Acarbose; D009638:Norepinephrine; D004837:Epinephrine