The plasma concentrations of secretin and vasoactive intestinal polypeptide (VIP) after long-term, strenuous exercise.

Twelve subjects (aged 21-38 years) participated in a 90-km cross-country ski race lasting 4.45-6.50 h. In order to investigate a metabolic role for secretin and vasoactive intestinal polypeptide (VIP) during long-term strenuous exercise, seven of the subjects were given an oral hypertonic glucose solution while the others had no nutrient intake immediately after the race. The plasma concentrations of secretin and VIP were greatly increased immediately after the race, and the levels were not normalized within 140 min, though there was a significant decrease after 80 min with rest. The post-race plasma levels of secretin and VIP showed a rapid and very marked decrease 15 min after ingestion of glucose, and the plasma levels had returned to control levels 60 min and 15 min respectively after glucose loading. The results indicate some metabolic function for secretin and VIP during long-term physical exercise.