Abstract

The purpose of the present study was to compare the plasma insulin levels in portal and peripheral veins in rats submitted to a prolonged exercise to exhaustion (X+/-SE: 67+/-7 Min). Plasma insulin levels were reduced significantly (p<0.01) during exercise in both the portal and peripheral venous circulation. The reduction was, however, more pronounced in the portal than in the peripheral vein (x:-113 vs -64 and -162 vs -88 pmol/l after 30 and 45 min of exercise, respectively), indicating that exercise reduced not only insulin secretion but also its removal. Accordingly, no significant differences were found for the portal/peripheral ratio of insulin at rest and during the first 45 min of exercise (1.86+/-0.2, 1.76+/-0.1, and 1.57+/-0.2 at rest, and after 30 and 45 min of exercise, respectively). This suggests that insulin removal during exercise is regulated in proportion to portal insulin concentrations. Verf.-Referat