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 (x̄±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 (x̄:-113 vs -64 and -162 vs -88 pmol·l-1 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.
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation