Effect of physical exercise on sensitivity and responsiveness to insulin in XXXX .

@entity1 @entity101 @entity2690 @entity413
The effect of acute physical exercise on insulin sensitivity and responsiveness of @entity413 uptake and hepatic @entity413 production was studied. Seven untrained @entity1 were subjected to four sequential euglycemic hyperinsulinemic clamps after rest (R), immediately after exercise (E), as well as 48 h after 60 min of 150 W ergometer exercise (ER). Insulin-mediated @entity413 uptake was higher on E and ER days compared with R days. Apparent Km decreased after exercise (52 +/- 3 R vs. 43 +/- 4 E and 40 +/- 3 ER microU/ml, means +/- SE) and Vmax increased (9.5 +/- 0.8 R vs. 10.9 +/- 0.7 E and 10.7 +/- 0.8 ER mg.min-1.kg-1). @entity413 oxidation increased with the increasing insulin infusion rate, and maximal @entity413 oxidation rate was lower on E days compared with R days. The maximal conversion rate of @entity413 to glycogen was higher on E and ER days (8.0 +/- 0.3 and 7.2 +/- 0.2, respectively) than on R days (5.7 +/- 0.6 mg.min-1 kg-1). Muscle glycogen synthase I activity was higher immediately after exercise and remained higher for the next 48 h. No change in any glucoregulatory hormone or metabolite could explain the @entity101 seen after exercise. In additional experiments (n = 3), no remaining effect existed 5 days after exercise. Both insulin and exercise suppressed the pancreatic secretion of insulin and @entity2690 . The conclusions drawn are that prolonged moderate exercise increases insulin action on @entity413 uptake in @entity1 by reducing apparent Km and increasing Vmax. This effect lasts 48 h but not 5 days. The @entity101 may be related to an exercise-induced increase in glycogen synthase activity.
