par Fery, Françoise ;Balasse, Edmond
Référence American journal of physiology: endocrinology and metabolism, 8, 4, page (E318-E325)
Publication Publié, 1983
Article révisé par les pairs
Résumé : The concentration of ketone bodies and their rate of transport (estimated with an infusion of β-[14C]-hydroxybutyrate) were determined before, during, and after exercise in overnight-fasted and 3- to 3-day-fasted subjects who walked on a treadmill for 2 h at approximately 50% of their V̇O(2max). In overnight-fasted subjects, exercise increased the rate of turnover (+125% after 2 h) and the metabolic clearance rate of ketone bodies whose concentration rose from 0.20 to 0.39 mM. Discontinuation of exercise was associated with a marked increase in ketone levels (+0.73 mM after 30 min of recovery) that was related to a further stimulation of ketogenesis (+19%) and to a marked drop of the metabolic clearance rate to below preexercise values. In sharp contrast with overnight-fasted subjects, starved subjects (with a resting ketone level averaging 5.7 mM) responded to work by a decrease in the turnover rate and in the concentration of ketones, their metabolic clearance rate remaining unchanged. Thus, the response of ketogenesis and muscular ketone uptake to exercise are both markedly influenced by the initial degree of fasting ketosis.