Abstract des Autors

Objective: The purpose of this study was to determine to what extent metabolic (glucose, fatty acids) and hormonal (insulin, adrenaline, noradrenaline) responses are modified according to age in women, after an oral glucose charge given at the beginning of a prolonged and moderate bicycle exercise. Eight prepubertal girls (9.7+/-0.4 years) and eight women (21.5+/-0.9 years) participated to this experiment. Methods: Venous blood samples were drawn at rest, at minute 3, 5, 10, 15, 30 of the exercise and after 30 minutes of recovery. Glucose ingestion took place between the 2nd and 3rd minute of the exercise. Results: During exercise, plasma glucose was always greater in girls than in women. The absolute values and the evolution of insulin were similar in both groups. Noradrenaline levels during the test did not differ from one group to the other, while adrenaline values appeared lower in girls. The ratio glucose/insulin was always greater in younger subjects during exercise, especially at the 5th (P<0.05) and 10th min (P<0.01), suggesting that the insulin sensitivity was lower in girls as compared to women. Conclusion: These results suggest a lower glucose tolerance in girls, which could be explained by a relative resistance to insulin already established at rest during the peripubertal period. This might contribute to a better lipolysis in younger subjects as demonstrated by greater plasma fatty acid values in this age group. Verf.-Referat